Defines | Typedefs | Functions

ogr_api.h File Reference

C API and defines for OGRFeature, OGRGeometry, and OGRDataSource related classes. More...

#include "cpl_progress.h"
#include "cpl_minixml.h"
#include "ogr_core.h"

Go to the source code of this file.

Typedefs

typedef void * OGRGeometryH
typedef void * OGRSpatialReferenceH
typedef void * OGRCoordinateTransformationH
typedef void * OGRFieldDefnH
typedef void * OGRFeatureDefnH
typedef void * OGRFeatureH
typedef void * OGRStyleTableH
typedef struct OGRGeomFieldDefnHS * OGRGeomFieldDefnH
typedef void * OGRLayerH
typedef void * OGRDataSourceH
typedef void * OGRSFDriverH
typedef void * OGRStyleMgrH
typedef void * OGRStyleToolH

Functions

OGRErr OGR_G_CreateFromWkb (unsigned char *, OGRSpatialReferenceH, OGRGeometryH *, int)
 Create a geometry object of the appropriate type from it's well known binary representation.
OGRErr OGR_G_CreateFromWkt (char **, OGRSpatialReferenceH, OGRGeometryH *)
 Create a geometry object of the appropriate type from it's well known text representation.
OGRErr OGR_G_CreateFromFgf (unsigned char *, OGRSpatialReferenceH, OGRGeometryH *, int, int *)
void OGR_G_DestroyGeometry (OGRGeometryH)
 Destroy geometry object.
OGRGeometryH OGR_G_CreateGeometry (OGRwkbGeometryType)
 Create an empty geometry of desired type.
OGRGeometryH OGR_G_ApproximateArcAngles (double dfCenterX, double dfCenterY, double dfZ, double dfPrimaryRadius, double dfSecondaryAxis, double dfRotation, double dfStartAngle, double dfEndAngle, double dfMaxAngleStepSizeDegrees)
 Stroke arc to linestring.
OGRGeometryH OGR_G_ForceToPolygon (OGRGeometryH)
 Convert to polygon.
OGRGeometryH OGR_G_ForceToLineString (OGRGeometryH)
 Convert to line string.
OGRGeometryH OGR_G_ForceToMultiPolygon (OGRGeometryH)
 Convert to multipolygon.
OGRGeometryH OGR_G_ForceToMultiPoint (OGRGeometryH)
 Convert to multipoint.
OGRGeometryH OGR_G_ForceToMultiLineString (OGRGeometryH)
 Convert to multilinestring.
OGRGeometryH OGR_G_ForceTo (OGRGeometryH hGeom, OGRwkbGeometryType eTargetType, char **papszOptions)
 Convert to another geometry type.
int OGR_G_GetDimension (OGRGeometryH)
 Get the dimension of this geometry.
int OGR_G_GetCoordinateDimension (OGRGeometryH)
 Get the dimension of the coordinates in this geometry.
void OGR_G_SetCoordinateDimension (OGRGeometryH, int)
 Set the coordinate dimension.
OGRGeometryH OGR_G_Clone (OGRGeometryH)
 Make a copy of this object.
void OGR_G_GetEnvelope (OGRGeometryH, OGREnvelope *)
 Computes and returns the bounding envelope for this geometry in the passed psEnvelope structure.
void OGR_G_GetEnvelope3D (OGRGeometryH, OGREnvelope3D *)
 Computes and returns the bounding envelope (3D) for this geometry in the passed psEnvelope structure.
OGRErr OGR_G_ImportFromWkb (OGRGeometryH, unsigned char *, int)
 Assign geometry from well known binary data.
OGRErr OGR_G_ExportToWkb (OGRGeometryH, OGRwkbByteOrder, unsigned char *)
 Convert a geometry well known binary format.
OGRErr OGR_G_ExportToIsoWkb (OGRGeometryH, OGRwkbByteOrder, unsigned char *)
 Convert a geometry into SFSQL 1.2 / ISO SQL/MM Part 3 well known binary format.
int OGR_G_WkbSize (OGRGeometryH hGeom)
 Returns size of related binary representation.
OGRErr OGR_G_ImportFromWkt (OGRGeometryH, char **)
 Assign geometry from well known text data.
OGRErr OGR_G_ExportToWkt (OGRGeometryH, char **)
 Convert a geometry into well known text format.
OGRErr OGR_G_ExportToIsoWkt (OGRGeometryH, char **)
 Convert a geometry into SFSQL 1.2 / ISO SQL/MM Part 3 well known text format.
OGRwkbGeometryType OGR_G_GetGeometryType (OGRGeometryH)
 Fetch geometry type.
const char * OGR_G_GetGeometryName (OGRGeometryH)
 Fetch WKT name for geometry type.
void OGR_G_DumpReadable (OGRGeometryH, FILE *, const char *)
 Dump geometry in well known text format to indicated output file.
void OGR_G_FlattenTo2D (OGRGeometryH)
 Convert geometry to strictly 2D.
void OGR_G_CloseRings (OGRGeometryH)
 Force rings to be closed.
OGRGeometryH OGR_G_CreateFromGML (const char *)
 Create geometry from GML.
char * OGR_G_ExportToGML (OGRGeometryH)
 Convert a geometry into GML format.
char * OGR_G_ExportToGMLEx (OGRGeometryH, char **papszOptions)
 Convert a geometry into GML format.
OGRGeometryH OGR_G_CreateFromGMLTree (const CPLXMLNode *)
CPLXMLNodeOGR_G_ExportToGMLTree (OGRGeometryH)
CPLXMLNodeOGR_G_ExportEnvelopeToGMLTree (OGRGeometryH)
char * OGR_G_ExportToKML (OGRGeometryH, const char *pszAltitudeMode)
 Convert a geometry into KML format.
char * OGR_G_ExportToJson (OGRGeometryH)
 Convert a geometry into GeoJSON format.
char * OGR_G_ExportToJsonEx (OGRGeometryH, char **papszOptions)
 Convert a geometry into GeoJSON format.
OGRGeometryH OGR_G_CreateGeometryFromJson (const char *)
void OGR_G_AssignSpatialReference (OGRGeometryH, OGRSpatialReferenceH)
 Assign spatial reference to this object.
OGRSpatialReferenceH OGR_G_GetSpatialReference (OGRGeometryH)
 Returns spatial reference system for geometry.
OGRErr OGR_G_Transform (OGRGeometryH, OGRCoordinateTransformationH)
 Apply arbitrary coordinate transformation to geometry.
OGRErr OGR_G_TransformTo (OGRGeometryH, OGRSpatialReferenceH)
 Transform geometry to new spatial reference system.
OGRGeometryH OGR_G_Simplify (OGRGeometryH hThis, double tolerance)
 Compute a simplified geometry.
OGRGeometryH OGR_G_SimplifyPreserveTopology (OGRGeometryH hThis, double tolerance)
 Simplify the geometry while preserving topology.
void OGR_G_Segmentize (OGRGeometryH hGeom, double dfMaxLength)
 Modify the geometry such it has no segment longer then the given distance.
int OGR_G_Intersects (OGRGeometryH, OGRGeometryH)
 Do these features intersect?
int OGR_G_Equals (OGRGeometryH, OGRGeometryH)
 Returns TRUE if two geometries are equivalent.
int OGR_G_Disjoint (OGRGeometryH, OGRGeometryH)
 Test for disjointness.
int OGR_G_Touches (OGRGeometryH, OGRGeometryH)
 Test for touching.
int OGR_G_Crosses (OGRGeometryH, OGRGeometryH)
 Test for crossing.
int OGR_G_Within (OGRGeometryH, OGRGeometryH)
 Test for containment.
int OGR_G_Contains (OGRGeometryH, OGRGeometryH)
 Test for containment.
int OGR_G_Overlaps (OGRGeometryH, OGRGeometryH)
 Test for overlap.
OGRGeometryH OGR_G_Boundary (OGRGeometryH)
 Compute boundary.
OGRGeometryH OGR_G_ConvexHull (OGRGeometryH)
 Compute convex hull.
OGRGeometryH OGR_G_Buffer (OGRGeometryH, double, int)
 Compute buffer of geometry.
OGRGeometryH OGR_G_Intersection (OGRGeometryH, OGRGeometryH)
 Compute intersection.
OGRGeometryH OGR_G_Union (OGRGeometryH, OGRGeometryH)
 Compute union.
OGRGeometryH OGR_G_UnionCascaded (OGRGeometryH)
 Compute union using cascading.
OGRGeometryH OGR_G_PointOnSurface (OGRGeometryH)
 Returns a point guaranteed to lie on the surface.
OGRGeometryH OGR_G_Difference (OGRGeometryH, OGRGeometryH)
 Compute difference.
OGRGeometryH OGR_G_SymDifference (OGRGeometryH, OGRGeometryH)
 Compute symmetric difference.
double OGR_G_Distance (OGRGeometryH, OGRGeometryH)
 Compute distance between two geometries.
double OGR_G_Length (OGRGeometryH)
 Compute length of a geometry.
double OGR_G_Area (OGRGeometryH)
 Compute geometry area.
int OGR_G_Centroid (OGRGeometryH, OGRGeometryH)
 Compute the geometry centroid.
OGRGeometryH OGR_G_Value (OGRGeometryH, double dfDistance)
 Fetch point at given distance along curve.
void OGR_G_Empty (OGRGeometryH)
 Clear geometry information.
int OGR_G_IsEmpty (OGRGeometryH)
 Test if the geometry is empty.
int OGR_G_IsValid (OGRGeometryH)
 Test if the geometry is valid.
int OGR_G_IsSimple (OGRGeometryH)
 Returns TRUE if the geometry is simple.
int OGR_G_IsRing (OGRGeometryH)
 Test if the geometry is a ring.
OGRGeometryH OGR_G_Polygonize (OGRGeometryH)
 Polygonizes a set of sparse edges.
int OGR_G_Intersect (OGRGeometryH, OGRGeometryH) CPL_WARN_DEPRECATED("Non standard method. Use OGR_G_Intersects() instead")
int OGR_G_Equal (OGRGeometryH, OGRGeometryH) CPL_WARN_DEPRECATED("Non standard method. Use OGR_G_Equals() instead")
OGRGeometryH OGR_G_SymmetricDifference (OGRGeometryH, OGRGeometryH) CPL_WARN_DEPRECATED("Non standard method. Use OGR_G_SymDifference() instead")
 Compute symmetric difference (deprecated).
double OGR_G_GetArea (OGRGeometryH) CPL_WARN_DEPRECATED("Non standard method. Use OGR_G_Area() instead")
 Compute geometry area (deprecated).
OGRGeometryH OGR_G_GetBoundary (OGRGeometryH) CPL_WARN_DEPRECATED("Non standard method. Use OGR_G_Boundary() instead")
 Compute boundary (deprecated).
int OGR_G_GetPointCount (OGRGeometryH)
 Fetch number of points from a geometry.
int OGR_G_GetPoints (OGRGeometryH hGeom, void *pabyX, int nXStride, void *pabyY, int nYStride, void *pabyZ, int nZStride)
 Returns all points of line string.
double OGR_G_GetX (OGRGeometryH, int)
 Fetch the x coordinate of a point from a geometry.
double OGR_G_GetY (OGRGeometryH, int)
 Fetch the x coordinate of a point from a geometry.
double OGR_G_GetZ (OGRGeometryH, int)
 Fetch the z coordinate of a point from a geometry.
void OGR_G_GetPoint (OGRGeometryH, int iPoint, double *, double *, double *)
 Fetch a point in line string or a point geometry.
void OGR_G_SetPointCount (OGRGeometryH hGeom, int nNewPointCount)
 Set number of points in a geometry.
void OGR_G_SetPoint (OGRGeometryH, int iPoint, double, double, double)
 Set the location of a vertex in a point or linestring geometry.
void OGR_G_SetPoint_2D (OGRGeometryH, int iPoint, double, double)
 Set the location of a vertex in a point or linestring geometry.
void OGR_G_AddPoint (OGRGeometryH, double, double, double)
 Add a point to a geometry (line string or point).
void OGR_G_AddPoint_2D (OGRGeometryH, double, double)
 Add a point to a geometry (line string or point).
void OGR_G_SetPoints (OGRGeometryH hGeom, int nPointsIn, void *pabyX, int nXStride, void *pabyY, int nYStride, void *pabyZ, int nZStride)
 Assign all points in a point or a line string geometry.
int OGR_G_GetGeometryCount (OGRGeometryH)
 Fetch the number of elements in a geometry or number of geometries in container.
OGRGeometryH OGR_G_GetGeometryRef (OGRGeometryH, int)
 Fetch geometry from a geometry container.
OGRErr OGR_G_AddGeometry (OGRGeometryH, OGRGeometryH)
 Add a geometry to a geometry container.
OGRErr OGR_G_AddGeometryDirectly (OGRGeometryH, OGRGeometryH)
 Add a geometry directly to an existing geometry container.
OGRErr OGR_G_RemoveGeometry (OGRGeometryH, int, int)
 Remove a geometry from an exiting geometry container.
int OGR_G_HasCurveGeometry (OGRGeometryH, int bLookForNonLinear)
 Returns if this geometry is or has curve geometry.
OGRGeometryH OGR_G_GetLinearGeometry (OGRGeometryH hGeom, double dfMaxAngleStepSizeDegrees, char **papszOptions)
 Return, possibly approximate, linear version of this geometry.
OGRGeometryH OGR_G_GetCurveGeometry (OGRGeometryH hGeom, char **papszOptions)
 Return curve version of this geometry.
OGRGeometryH OGRBuildPolygonFromEdges (OGRGeometryH hLinesAsCollection, int bBestEffort, int bAutoClose, double dfTolerance, OGRErr *peErr)
 Build a ring from a bunch of arcs.
OGRErr OGRSetGenerate_DB2_V72_BYTE_ORDER (int bGenerate_DB2_V72_BYTE_ORDER)
 Special entry point to enable the hack for generating DB2 V7.2 style WKB.
int OGRGetGenerate_DB2_V72_BYTE_ORDER (void)
void OGRSetNonLinearGeometriesEnabledFlag (int bFlag)
 Set flag to enable/disable returning non-linear geometries in the C API.
int OGRGetNonLinearGeometriesEnabledFlag (void)
 Get flag to enable/disable returning non-linear geometries in the C API.
OGRFieldDefnH OGR_Fld_Create (const char *, OGRFieldType) CPL_WARN_UNUSED_RESULT
 Create a new field definition.
void OGR_Fld_Destroy (OGRFieldDefnH)
 Destroy a field definition.
void OGR_Fld_SetName (OGRFieldDefnH, const char *)
 Reset the name of this field.
const char * OGR_Fld_GetNameRef (OGRFieldDefnH)
 Fetch name of this field.
OGRFieldType OGR_Fld_GetType (OGRFieldDefnH)
 Fetch type of this field.
void OGR_Fld_SetType (OGRFieldDefnH, OGRFieldType)
 Set the type of this field.
OGRFieldSubType OGR_Fld_GetSubType (OGRFieldDefnH)
 Fetch subtype of this field.
void OGR_Fld_SetSubType (OGRFieldDefnH, OGRFieldSubType)
 Set the subtype of this field.
OGRJustification OGR_Fld_GetJustify (OGRFieldDefnH)
 Get the justification for this field.
void OGR_Fld_SetJustify (OGRFieldDefnH, OGRJustification)
 Set the justification for this field.
int OGR_Fld_GetWidth (OGRFieldDefnH)
 Get the formatting width for this field.
void OGR_Fld_SetWidth (OGRFieldDefnH, int)
 Set the formatting width for this field in characters.
int OGR_Fld_GetPrecision (OGRFieldDefnH)
 Get the formatting precision for this field.
void OGR_Fld_SetPrecision (OGRFieldDefnH, int)
 Set the formatting precision for this field in characters.
void OGR_Fld_Set (OGRFieldDefnH, const char *, OGRFieldType, int, int, OGRJustification)
 Set defining parameters for a field in one call.
int OGR_Fld_IsIgnored (OGRFieldDefnH hDefn)
 Return whether this field should be omitted when fetching features.
void OGR_Fld_SetIgnored (OGRFieldDefnH hDefn, int)
 Set whether this field should be omitted when fetching features.
const char * OGR_GetFieldTypeName (OGRFieldType)
 Fetch human readable name for a field type.
const char * OGR_GetFieldSubTypeName (OGRFieldSubType)
 Fetch human readable name for a field subtype.
int OGR_AreTypeSubTypeCompatible (OGRFieldType eType, OGRFieldSubType eSubType)
 Return if type and subtype are compatible.
OGRGeomFieldDefnH OGR_GFld_Create (const char *, OGRwkbGeometryType) CPL_WARN_UNUSED_RESULT
 Create a new field geometry definition.
void OGR_GFld_Destroy (OGRGeomFieldDefnH)
 Destroy a geometry field definition.
void OGR_GFld_SetName (OGRGeomFieldDefnH, const char *)
 Reset the name of this field.
const char * OGR_GFld_GetNameRef (OGRGeomFieldDefnH)
 Fetch name of this field.
OGRwkbGeometryType OGR_GFld_GetType (OGRGeomFieldDefnH)
 Fetch geometry type of this field.
void OGR_GFld_SetType (OGRGeomFieldDefnH, OGRwkbGeometryType)
 Set the geometry type of this field.
OGRSpatialReferenceH OGR_GFld_GetSpatialRef (OGRGeomFieldDefnH)
 Fetch spatial reference system of this field.
void OGR_GFld_SetSpatialRef (OGRGeomFieldDefnH, OGRSpatialReferenceH hSRS)
 Set the spatial reference of this field.
int OGR_GFld_IsIgnored (OGRGeomFieldDefnH hDefn)
 Return whether this field should be omitted when fetching features.
void OGR_GFld_SetIgnored (OGRGeomFieldDefnH hDefn, int)
 Set whether this field should be omitted when fetching features.
OGRFeatureDefnH OGR_FD_Create (const char *) CPL_WARN_UNUSED_RESULT
 Create a new feature definition object to hold the field definitions.
void OGR_FD_Destroy (OGRFeatureDefnH)
 Destroy a feature definition object and release all memory associated with it.
void OGR_FD_Release (OGRFeatureDefnH)
 Drop a reference, and destroy if unreferenced.
const char * OGR_FD_GetName (OGRFeatureDefnH)
 Get name of the OGRFeatureDefn passed as an argument.
int OGR_FD_GetFieldCount (OGRFeatureDefnH)
 Fetch number of fields on the passed feature definition.
OGRFieldDefnH OGR_FD_GetFieldDefn (OGRFeatureDefnH, int)
 Fetch field definition of the passed feature definition.
int OGR_FD_GetFieldIndex (OGRFeatureDefnH, const char *)
 Find field by name.
void OGR_FD_AddFieldDefn (OGRFeatureDefnH, OGRFieldDefnH)
 Add a new field definition to the passed feature definition.
OGRErr OGR_FD_DeleteFieldDefn (OGRFeatureDefnH hDefn, int iField)
 Delete an existing field definition.
OGRErr OGR_FD_ReorderFieldDefns (OGRFeatureDefnH hDefn, int *panMap)
OGRwkbGeometryType OGR_FD_GetGeomType (OGRFeatureDefnH)
 Fetch the geometry base type of the passed feature definition.
void OGR_FD_SetGeomType (OGRFeatureDefnH, OGRwkbGeometryType)
 Assign the base geometry type for the passed layer (the same as the feature definition).
int OGR_FD_IsGeometryIgnored (OGRFeatureDefnH)
 Determine whether the geometry can be omitted when fetching features.
void OGR_FD_SetGeometryIgnored (OGRFeatureDefnH, int)
 Set whether the geometry can be omitted when fetching features.
int OGR_FD_IsStyleIgnored (OGRFeatureDefnH)
 Determine whether the style can be omitted when fetching features.
void OGR_FD_SetStyleIgnored (OGRFeatureDefnH, int)
 Set whether the style can be omitted when fetching features.
int OGR_FD_Reference (OGRFeatureDefnH)
 Increments the reference count by one.
int OGR_FD_Dereference (OGRFeatureDefnH)
 Decrements the reference count by one.
int OGR_FD_GetReferenceCount (OGRFeatureDefnH)
 Fetch current reference count.
int OGR_FD_GetGeomFieldCount (OGRFeatureDefnH hFDefn)
 Fetch number of geometry fields on the passed feature definition.
OGRGeomFieldDefnH OGR_FD_GetGeomFieldDefn (OGRFeatureDefnH hFDefn, int i)
 Fetch geometry field definition of the passed feature definition.
int OGR_FD_GetGeomFieldIndex (OGRFeatureDefnH hFDefn, const char *pszName)
 Find geometry field by name.
void OGR_FD_AddGeomFieldDefn (OGRFeatureDefnH hFDefn, OGRGeomFieldDefnH hGFldDefn)
 Add a new field definition to the passed feature definition.
OGRErr OGR_FD_DeleteGeomFieldDefn (OGRFeatureDefnH hFDefn, int iGeomField)
 Delete an existing geometry field definition.
int OGR_FD_IsSame (OGRFeatureDefnH hFDefn, OGRFeatureDefnH hOtherFDefn)
 Test if the feature definition is identical to the other one.
OGRFeatureH OGR_F_Create (OGRFeatureDefnH) CPL_WARN_UNUSED_RESULT
 Feature factory.
void OGR_F_Destroy (OGRFeatureH)
 Destroy feature.
OGRFeatureDefnH OGR_F_GetDefnRef (OGRFeatureH)
 Fetch feature definition.
OGRErr OGR_F_SetGeometryDirectly (OGRFeatureH, OGRGeometryH)
 Set feature geometry.
OGRErr OGR_F_SetGeometry (OGRFeatureH, OGRGeometryH)
 Set feature geometry.
OGRGeometryH OGR_F_GetGeometryRef (OGRFeatureH)
 Fetch an handle to feature geometry.
OGRGeometryH OGR_F_StealGeometry (OGRFeatureH)
 Take away ownership of geometry.
OGRFeatureH OGR_F_Clone (OGRFeatureH)
 Duplicate feature.
int OGR_F_Equal (OGRFeatureH, OGRFeatureH)
 Test if two features are the same.
int OGR_F_GetFieldCount (OGRFeatureH)
 Fetch number of fields on this feature This will always be the same as the field count for the OGRFeatureDefn.
OGRFieldDefnH OGR_F_GetFieldDefnRef (OGRFeatureH, int)
 Fetch definition for this field.
int OGR_F_GetFieldIndex (OGRFeatureH, const char *)
 Fetch the field index given field name.
int OGR_F_IsFieldSet (OGRFeatureH, int)
 Test if a field has ever been assigned a value or not.
void OGR_F_UnsetField (OGRFeatureH, int)
 Clear a field, marking it as unset.
OGRFieldOGR_F_GetRawFieldRef (OGRFeatureH, int)
 Fetch an handle to the internal field value given the index.
int OGR_F_GetFieldAsInteger (OGRFeatureH, int)
 Fetch field value as integer.
double OGR_F_GetFieldAsDouble (OGRFeatureH, int)
 Fetch field value as a double.
const char * OGR_F_GetFieldAsString (OGRFeatureH, int)
 Fetch field value as a string.
const int * OGR_F_GetFieldAsIntegerList (OGRFeatureH, int, int *)
 Fetch field value as a list of integers.
const double * OGR_F_GetFieldAsDoubleList (OGRFeatureH, int, int *)
 Fetch field value as a list of doubles.
char ** OGR_F_GetFieldAsStringList (OGRFeatureH, int)
 Fetch field value as a list of strings.
GByte * OGR_F_GetFieldAsBinary (OGRFeatureH, int, int *)
 Fetch field value as binary.
int OGR_F_GetFieldAsDateTime (OGRFeatureH, int, int *, int *, int *, int *, int *, int *, int *)
 Fetch field value as date and time.
void OGR_F_SetFieldInteger (OGRFeatureH, int, int)
 Set field to integer value.
void OGR_F_SetFieldDouble (OGRFeatureH, int, double)
 Set field to double value.
void OGR_F_SetFieldString (OGRFeatureH, int, const char *)
 Set field to string value.
void OGR_F_SetFieldIntegerList (OGRFeatureH, int, int, int *)
 Set field to list of integers value.
void OGR_F_SetFieldDoubleList (OGRFeatureH, int, int, double *)
 Set field to list of doubles value.
void OGR_F_SetFieldStringList (OGRFeatureH, int, char **)
 Set field to list of strings value.
void OGR_F_SetFieldRaw (OGRFeatureH, int, OGRField *)
 Set field.
void OGR_F_SetFieldBinary (OGRFeatureH, int, int, GByte *)
 Set field to binary data.
void OGR_F_SetFieldDateTime (OGRFeatureH, int, int, int, int, int, int, int, int)
 Set field to datetime.
int OGR_F_GetGeomFieldCount (OGRFeatureH hFeat)
 Fetch number of geometry fields on this feature This will always be the same as the geometry field count for the OGRFeatureDefn.
OGRGeomFieldDefnH OGR_F_GetGeomFieldDefnRef (OGRFeatureH hFeat, int iField)
 Fetch definition for this geometry field.
int OGR_F_GetGeomFieldIndex (OGRFeatureH hFeat, const char *pszName)
 Fetch the geometry field index given geometry field name.
OGRGeometryH OGR_F_GetGeomFieldRef (OGRFeatureH hFeat, int iField)
 Fetch an handle to feature geometry.
OGRErr OGR_F_SetGeomFieldDirectly (OGRFeatureH hFeat, int iField, OGRGeometryH hGeom)
 Set feature geometry of a specified geometry field.
OGRErr OGR_F_SetGeomField (OGRFeatureH hFeat, int iField, OGRGeometryH hGeom)
 Set feature geometry of a specified geometry field.
long OGR_F_GetFID (OGRFeatureH)
 Get feature identifier.
OGRErr OGR_F_SetFID (OGRFeatureH, long)
 Set the feature identifier.
void OGR_F_DumpReadable (OGRFeatureH, FILE *)
 Dump this feature in a human readable form.
OGRErr OGR_F_SetFrom (OGRFeatureH, OGRFeatureH, int)
 Set one feature from another.
OGRErr OGR_F_SetFromWithMap (OGRFeatureH, OGRFeatureH, int, int *)
 Set one feature from another.
const char * OGR_F_GetStyleString (OGRFeatureH)
 Fetch style string for this feature.
void OGR_F_SetStyleString (OGRFeatureH, const char *)
 Set feature style string.
void OGR_F_SetStyleStringDirectly (OGRFeatureH, char *)
 Set feature style string.
OGRStyleTableH OGR_F_GetStyleTable (OGRFeatureH)
void OGR_F_SetStyleTableDirectly (OGRFeatureH, OGRStyleTableH)
void OGR_F_SetStyleTable (OGRFeatureH, OGRStyleTableH)
const char * OGR_L_GetName (OGRLayerH)
 Return the layer name.
OGRwkbGeometryType OGR_L_GetGeomType (OGRLayerH)
 Return the layer geometry type.
OGRGeometryH OGR_L_GetSpatialFilter (OGRLayerH)
 This function returns the current spatial filter for this layer.
void OGR_L_SetSpatialFilter (OGRLayerH, OGRGeometryH)
 Set a new spatial filter.
void OGR_L_SetSpatialFilterRect (OGRLayerH, double, double, double, double)
 Set a new rectangular spatial filter.
void OGR_L_SetSpatialFilterEx (OGRLayerH, int iGeomField, OGRGeometryH hGeom)
 Set a new spatial filter.
void OGR_L_SetSpatialFilterRectEx (OGRLayerH, int iGeomField, double dfMinX, double dfMinY, double dfMaxX, double dfMaxY)
 Set a new rectangular spatial filter.
OGRErr OGR_L_SetAttributeFilter (OGRLayerH, const char *)
 Set a new attribute query.
void OGR_L_ResetReading (OGRLayerH)
 Reset feature reading to start on the first feature.
OGRFeatureH OGR_L_GetNextFeature (OGRLayerH)
 Fetch the next available feature from this layer.
OGRErr OGR_L_SetNextByIndex (OGRLayerH, long)
 Move read cursor to the nIndex'th feature in the current resultset.
OGRFeatureH OGR_L_GetFeature (OGRLayerH, long)
 Fetch a feature by its identifier.
OGRErr OGR_L_SetFeature (OGRLayerH, OGRFeatureH)
 Rewrite an existing feature.
OGRErr OGR_L_CreateFeature (OGRLayerH, OGRFeatureH)
 Create and write a new feature within a layer.
OGRErr OGR_L_DeleteFeature (OGRLayerH, long)
 Delete feature from layer.
OGRFeatureDefnH OGR_L_GetLayerDefn (OGRLayerH)
 Fetch the schema information for this layer.
OGRSpatialReferenceH OGR_L_GetSpatialRef (OGRLayerH)
 Fetch the spatial reference system for this layer.
int OGR_L_FindFieldIndex (OGRLayerH, const char *, int bExactMatch)
 Find the index of field in a layer.
int OGR_L_GetFeatureCount (OGRLayerH, int)
 Fetch the feature count in this layer.
OGRErr OGR_L_GetExtent (OGRLayerH, OGREnvelope *, int)
 Fetch the extent of this layer.
OGRErr OGR_L_GetExtentEx (OGRLayerH, int iGeomField, OGREnvelope *psExtent, int bForce)
 Fetch the extent of this layer, on the specified geometry field.
int OGR_L_TestCapability (OGRLayerH, const char *)
 Test if this layer supported the named capability.
OGRErr OGR_L_CreateField (OGRLayerH, OGRFieldDefnH, int)
 Create a new field on a layer.
OGRErr OGR_L_CreateGeomField (OGRLayerH hLayer, OGRGeomFieldDefnH hFieldDefn, int bForce)
 Create a new geometry field on a layer.
OGRErr OGR_L_DeleteField (OGRLayerH, int iField)
 Create a new field on a layer.
OGRErr OGR_L_ReorderFields (OGRLayerH, int *panMap)
 Reorder all the fields of a layer.
OGRErr OGR_L_ReorderField (OGRLayerH, int iOldFieldPos, int iNewFieldPos)
 Reorder an existing field on a layer.
OGRErr OGR_L_AlterFieldDefn (OGRLayerH, int iField, OGRFieldDefnH hNewFieldDefn, int nFlags)
 Alter the definition of an existing field on a layer.
OGRErr OGR_L_StartTransaction (OGRLayerH)
 For datasources which support transactions, StartTransaction creates a transaction.
OGRErr OGR_L_CommitTransaction (OGRLayerH)
 For datasources which support transactions, CommitTransaction commits a transaction.
OGRErr OGR_L_RollbackTransaction (OGRLayerH)
 For datasources which support transactions, RollbackTransaction will roll back a datasource to its state before the start of the current transaction.
int OGR_L_Reference (OGRLayerH)
int OGR_L_Dereference (OGRLayerH)
int OGR_L_GetRefCount (OGRLayerH)
OGRErr OGR_L_SyncToDisk (OGRLayerH)
 Flush pending changes to disk.
GIntBig OGR_L_GetFeaturesRead (OGRLayerH)
const char * OGR_L_GetFIDColumn (OGRLayerH)
 This method returns the name of the underlying database column being used as the FID column, or "" if not supported.
const char * OGR_L_GetGeometryColumn (OGRLayerH)
 This method returns the name of the underlying database column being used as the geometry column, or "" if not supported.
OGRStyleTableH OGR_L_GetStyleTable (OGRLayerH)
void OGR_L_SetStyleTableDirectly (OGRLayerH, OGRStyleTableH)
void OGR_L_SetStyleTable (OGRLayerH, OGRStyleTableH)
OGRErr OGR_L_SetIgnoredFields (OGRLayerH, const char **)
 Set which fields can be omitted when retrieving features from the layer.
OGRErr OGR_L_Intersection (OGRLayerH, OGRLayerH, OGRLayerH, char **, GDALProgressFunc, void *)
 Intersection of two layers.
OGRErr OGR_L_Union (OGRLayerH, OGRLayerH, OGRLayerH, char **, GDALProgressFunc, void *)
 Union of two layers.
OGRErr OGR_L_SymDifference (OGRLayerH, OGRLayerH, OGRLayerH, char **, GDALProgressFunc, void *)
 Symmetrical difference of two layers.
OGRErr OGR_L_Identity (OGRLayerH, OGRLayerH, OGRLayerH, char **, GDALProgressFunc, void *)
 Identify the features of this layer with the ones from the identity layer.
OGRErr OGR_L_Update (OGRLayerH, OGRLayerH, OGRLayerH, char **, GDALProgressFunc, void *)
 Update this layer with features from the update layer.
OGRErr OGR_L_Clip (OGRLayerH, OGRLayerH, OGRLayerH, char **, GDALProgressFunc, void *)
 Clip off areas that are not covered by the method layer.
OGRErr OGR_L_Erase (OGRLayerH, OGRLayerH, OGRLayerH, char **, GDALProgressFunc, void *)
 Remove areas that are covered by the method layer.
void OGR_DS_Destroy (OGRDataSourceH)
 Closes opened datasource and releases allocated resources.
const char * OGR_DS_GetName (OGRDataSourceH)
 Returns the name of the data source.
int OGR_DS_GetLayerCount (OGRDataSourceH)
 Get the number of layers in this data source.
OGRLayerH OGR_DS_GetLayer (OGRDataSourceH, int)
 Fetch a layer by index.
OGRLayerH OGR_DS_GetLayerByName (OGRDataSourceH, const char *)
 Fetch a layer by name.
OGRErr OGR_DS_DeleteLayer (OGRDataSourceH, int)
 Delete the indicated layer from the datasource.
OGRSFDriverH OGR_DS_GetDriver (OGRDataSourceH)
 Returns the driver that the dataset was opened with.
OGRLayerH OGR_DS_CreateLayer (OGRDataSourceH, const char *, OGRSpatialReferenceH, OGRwkbGeometryType, char **)
 This function attempts to create a new layer on the data source with the indicated name, coordinate system, geometry type.
OGRLayerH OGR_DS_CopyLayer (OGRDataSourceH, OGRLayerH, const char *, char **)
 Duplicate an existing layer.
int OGR_DS_TestCapability (OGRDataSourceH, const char *)
 Test if capability is available.
OGRLayerH OGR_DS_ExecuteSQL (OGRDataSourceH, const char *, OGRGeometryH, const char *)
 Execute an SQL statement against the data store.
void OGR_DS_ReleaseResultSet (OGRDataSourceH, OGRLayerH)
 Release results of OGR_DS_ExecuteSQL().
int OGR_DS_Reference (OGRDataSourceH)
int OGR_DS_Dereference (OGRDataSourceH)
int OGR_DS_GetRefCount (OGRDataSourceH)
int OGR_DS_GetSummaryRefCount (OGRDataSourceH)
OGRErr OGR_DS_SyncToDisk (OGRDataSourceH)
OGRStyleTableH OGR_DS_GetStyleTable (OGRDataSourceH)
void OGR_DS_SetStyleTableDirectly (OGRDataSourceH, OGRStyleTableH)
void OGR_DS_SetStyleTable (OGRDataSourceH, OGRStyleTableH)
const char * OGR_Dr_GetName (OGRSFDriverH)
 Fetch name of driver (file format).
OGRDataSourceH OGR_Dr_Open (OGRSFDriverH, const char *, int) CPL_WARN_UNUSED_RESULT
 Attempt to open file with this driver.
int OGR_Dr_TestCapability (OGRSFDriverH, const char *)
 Test if capability is available.
OGRDataSourceH OGR_Dr_CreateDataSource (OGRSFDriverH, const char *, char **) CPL_WARN_UNUSED_RESULT
 This function attempts to create a new data source based on the passed driver.
OGRDataSourceH OGR_Dr_CopyDataSource (OGRSFDriverH, OGRDataSourceH, const char *, char **) CPL_WARN_UNUSED_RESULT
 This function creates a new datasource by copying all the layers from the source datasource.
OGRErr OGR_Dr_DeleteDataSource (OGRSFDriverH, const char *)
 Delete a datasource.
OGRDataSourceH OGROpen (const char *, int, OGRSFDriverH *) CPL_WARN_UNUSED_RESULT
 Open a file / data source with one of the registered drivers.
OGRDataSourceH OGROpenShared (const char *, int, OGRSFDriverH *) CPL_WARN_UNUSED_RESULT
OGRErr OGRReleaseDataSource (OGRDataSourceH)
 Drop a reference to this datasource, and if the reference count drops to zero close (destroy) the datasource.
void OGRRegisterDriver (OGRSFDriverH)
void OGRDeregisterDriver (OGRSFDriverH)
int OGRGetDriverCount (void)
 Fetch the number of registered drivers.
OGRSFDriverH OGRGetDriver (int)
 Fetch the indicated driver.
OGRSFDriverH OGRGetDriverByName (const char *)
 Fetch the indicated driver.
int OGRGetOpenDSCount (void)
OGRDataSourceH OGRGetOpenDS (int iDS)
void OGRRegisterAll (void)
 Register all drivers.
void OGRCleanupAll (void)
 Cleanup all OGR related resources.
OGRStyleMgrH OGR_SM_Create (OGRStyleTableH hStyleTable) CPL_WARN_UNUSED_RESULT
 OGRStyleMgr factory.
void OGR_SM_Destroy (OGRStyleMgrH hSM)
 Destroy Style Manager.
const char * OGR_SM_InitFromFeature (OGRStyleMgrH hSM, OGRFeatureH hFeat)
 Initialize style manager from the style string of a feature.
int OGR_SM_InitStyleString (OGRStyleMgrH hSM, const char *pszStyleString)
 Initialize style manager from the style string.
int OGR_SM_GetPartCount (OGRStyleMgrH hSM, const char *pszStyleString)
 Get the number of parts in a style.
OGRStyleToolH OGR_SM_GetPart (OGRStyleMgrH hSM, int nPartId, const char *pszStyleString)
 Fetch a part (style tool) from the current style.
int OGR_SM_AddPart (OGRStyleMgrH hSM, OGRStyleToolH hST)
 Add a part (style tool) to the current style.
int OGR_SM_AddStyle (OGRStyleMgrH hSM, const char *pszStyleName, const char *pszStyleString)
 Add a style to the current style table.
OGRStyleToolH OGR_ST_Create (OGRSTClassId eClassId) CPL_WARN_UNUSED_RESULT
 OGRStyleTool factory.
void OGR_ST_Destroy (OGRStyleToolH hST)
 Destroy Style Tool.
OGRSTClassId OGR_ST_GetType (OGRStyleToolH hST)
 Determine type of Style Tool.
OGRSTUnitId OGR_ST_GetUnit (OGRStyleToolH hST)
 Get Style Tool units.
void OGR_ST_SetUnit (OGRStyleToolH hST, OGRSTUnitId eUnit, double dfGroundPaperScale)
 Set Style Tool units.
const char * OGR_ST_GetParamStr (OGRStyleToolH hST, int eParam, int *bValueIsNull)
 Get Style Tool parameter value as string.
int OGR_ST_GetParamNum (OGRStyleToolH hST, int eParam, int *bValueIsNull)
 Get Style Tool parameter value as an integer.
double OGR_ST_GetParamDbl (OGRStyleToolH hST, int eParam, int *bValueIsNull)
 Get Style Tool parameter value as a double.
void OGR_ST_SetParamStr (OGRStyleToolH hST, int eParam, const char *pszValue)
 Set Style Tool parameter value from a string.
void OGR_ST_SetParamNum (OGRStyleToolH hST, int eParam, int nValue)
 Set Style Tool parameter value from an integer.
void OGR_ST_SetParamDbl (OGRStyleToolH hST, int eParam, double dfValue)
 Set Style Tool parameter value from a double.
const char * OGR_ST_GetStyleString (OGRStyleToolH hST)
 Get the style string for this Style Tool.
int OGR_ST_GetRGBFromString (OGRStyleToolH hST, const char *pszColor, int *pnRed, int *pnGreen, int *pnBlue, int *pnAlpha)
 Return the r,g,b,a components of a color encoded in #RRGGBB[AA] format.
OGRStyleTableH OGR_STBL_Create (void) CPL_WARN_UNUSED_RESULT
 OGRStyleTable factory.
void OGR_STBL_Destroy (OGRStyleTableH hSTBL)
 Destroy Style Table.
int OGR_STBL_AddStyle (OGRStyleTableH hStyleTable, const char *pszName, const char *pszStyleString)
 Add a new style in the table.
int OGR_STBL_SaveStyleTable (OGRStyleTableH hStyleTable, const char *pszFilename)
 Save a style table to a file.
int OGR_STBL_LoadStyleTable (OGRStyleTableH hStyleTable, const char *pszFilename)
 Load a style table from a file.
const char * OGR_STBL_Find (OGRStyleTableH hStyleTable, const char *pszName)
 Get a style string by name.
void OGR_STBL_ResetStyleStringReading (OGRStyleTableH hStyleTable)
 Reset the next style pointer to 0.
const char * OGR_STBL_GetNextStyle (OGRStyleTableH hStyleTable)
 Get the next style string from the table.
const char * OGR_STBL_GetLastStyleName (OGRStyleTableH hStyleTable)
 Get the style name of the last style string fetched with OGR_STBL_GetNextStyle.

Detailed Description

C API and defines for OGRFeature, OGRGeometry, and OGRDataSource related classes.

See also: ogr_geometry.h, ogr_feature.h, ogrsf_frmts.h, ogr_featurestyle.h


Function Documentation

int OGR_AreTypeSubTypeCompatible ( OGRFieldType  eType,
OGRFieldSubType  eSubType 
)

Return if type and subtype are compatible.

Parameters:
eType the field type.
eSubType the field subtype.
Returns:
TRUE if type and subtype are compatible
Since:
GDAL 2.0
OGRDataSourceH OGR_Dr_CopyDataSource ( OGRSFDriverH  hDriver,
OGRDataSourceH  hSrcDS,
const char *  pszNewName,
char **  papszOptions 
)

This function creates a new datasource by copying all the layers from the source datasource.

It is important to call OGR_DS_Destroy() when the datasource is no longer used to ensure that all data has been properly flushed to disk.

Deprecated:
Use GDALCreateCopy() in GDAL 2.0
Parameters:
hDriver handle to the driver on which data source creation is based.
hSrcDS source datasource
pszNewName the name for the new data source.
papszOptions a StringList of name=value options. Options are driver specific, and driver information can be found at the following url: http://www.gdal.org/ogr/ogr_formats.html
Returns:
NULL is returned on failure, or a new OGRDataSource handle on success.
OGRDataSourceH OGR_Dr_CreateDataSource ( OGRSFDriverH  hDriver,
const char *  pszName,
char **  papszOptions 
)

This function attempts to create a new data source based on the passed driver.

The papszOptions argument can be used to control driver specific creation options. These options are normally documented in the format specific documentation.

It is important to call OGR_DS_Destroy() when the datasource is no longer used to ensure that all data has been properly flushed to disk.

Deprecated:
Use GDALCreate() in GDAL 2.0
Parameters:
hDriver handle to the driver on which data source creation is based.
pszName the name for the new data source. UTF-8 encoded.
papszOptions a StringList of name=value options. Options are driver specific, and driver information can be found at the following url: http://www.gdal.org/ogr/ogr_formats.html
Returns:
NULL is returned on failure, or a new OGRDataSource handle on success.
OGRErr OGR_Dr_DeleteDataSource ( OGRSFDriverH  hDriver,
const char *  pszDataSource 
)

Delete a datasource.

Delete (from the disk, in the database, ...) the named datasource. Normally it would be safest if the datasource was not open at the time.

Whether this is a supported operation on this driver case be tested using TestCapability() on ODrCDeleteDataSource.

Deprecated:
Use GDALDeleteDataset() in GDAL 2
Parameters:
hDriver handle to the driver on which data source deletion is based.
pszDataSource the name of the datasource to delete.
Returns:
OGRERR_NONE on success, and OGRERR_UNSUPPORTED_OPERATION if this is not supported by this driver.
const char * OGR_Dr_GetName ( OGRSFDriverH  hDriver  ) 

Fetch name of driver (file format).

This name should be relatively short (10-40 characters), and should reflect the underlying file format. For instance "ESRI Shapefile".

This function is the same as the C++ method OGRSFDriver::GetName().

Parameters:
hDriver handle to the the driver to get the name from.
Returns:
driver name. This is an internal string and should not be modified or freed.
OGRDataSourceH OGR_Dr_Open ( OGRSFDriverH  hDriver,
const char *  pszName,
int  bUpdate 
)

Attempt to open file with this driver.

Deprecated:
Use GDALOpenEx() in GDAL 2.0
Parameters:
hDriver handle to the driver that is used to open file.
pszName the name of the file, or data source to try and open.
bUpdate TRUE if update access is required, otherwise FALSE (the default).
Returns:
NULL on error or if the pass name is not supported by this driver, otherwise an handle to an OGRDataSource. This OGRDataSource should be closed by deleting the object when it is no longer needed.
int OGR_Dr_TestCapability ( OGRSFDriverH  hDriver,
const char *  pszCap 
)

Test if capability is available.

One of the following data source capability names can be passed into this function, and a TRUE or FALSE value will be returned indicating whether or not the capability is available for this object.

  • ODrCCreateDataSource: True if this driver can support creating data sources.

  • ODrCDeleteDataSource: True if this driver supports deleting data sources.

The #define macro forms of the capability names should be used in preference to the strings themselves to avoid mispelling.

Deprecated:
Use GDALGetMetadataItem(hDriver, GDAL_DCAP_CREATE) in GDAL 2.0
Parameters:
hDriver handle to the driver to test the capability against.
pszCap the capability to test.
Returns:
TRUE if capability available otherwise FALSE.
OGRLayerH OGR_DS_CopyLayer ( OGRDataSourceH  hDS,
OGRLayerH  hSrcLayer,
const char *  pszNewName,
char **  papszOptions 
)

Duplicate an existing layer.

This function creates a new layer, duplicate the field definitions of the source layer and then duplicate each features of the source layer. The papszOptions argument can be used to control driver specific creation options. These options are normally documented in the format specific documentation. The source layer may come from another dataset.

Deprecated:
Use GDALDatasetCopyLayer() in GDAL 2.0
Parameters:
hDS handle to the data source where to create the new layer
hSrcLayer handle to the source layer.
pszNewName the name of the layer to create.
papszOptions a StringList of name=value options. Options are driver specific.
Returns:
an handle to the layer, or NULL if an error occurs.
OGRLayerH OGR_DS_CreateLayer ( OGRDataSourceH  hDS,
const char *  pszName,
OGRSpatialReferenceH  hSpatialRef,
OGRwkbGeometryType  eType,
char **  papszOptions 
)

This function attempts to create a new layer on the data source with the indicated name, coordinate system, geometry type.

The papszOptions argument can be used to control driver specific creation options. These options are normally documented in the format specific documentation.

Deprecated:
Use GDALDatasetCreateLayer() in GDAL 2.0
Parameters:
hDS The dataset handle.
pszName the name for the new layer. This should ideally not match any existing layer on the datasource.
hSpatialRef handle to the coordinate system to use for the new layer, or NULL if no coordinate system is available.
eType the geometry type for the layer. Use wkbUnknown if there are no constraints on the types geometry to be written.
papszOptions a StringList of name=value options. Options are driver specific, and driver information can be found at the following url: http://www.gdal.org/ogr/ogr_formats.html
Returns:
NULL is returned on failure, or a new OGRLayer handle on success.

Example:

#include "ogrsf_frmts.h" 
#include "cpl_string.h"

...

        OGRLayerH *hLayer;
        char     **papszOptions;

        if( OGR_DS_TestCapability( hDS, ODsCCreateLayer ) )
        {
            ...
        }

        papszOptions = CSLSetNameValue( papszOptions, "DIM", "2" );
        hLayer = OGR_DS_CreateLayer( hDS, "NewLayer", NULL, wkbUnknown,
                                     papszOptions );
        CSLDestroy( papszOptions );

        if( hLayer == NULL )
        {
            ...
        }        
OGRErr OGR_DS_DeleteLayer ( OGRDataSourceH  hDS,
int  iLayer 
)

Delete the indicated layer from the datasource.

If this method is supported the ODsCDeleteLayer capability will test TRUE on the OGRDataSource.

Deprecated:
Use GDALDatasetDeleteLayer() in GDAL 2.0
Parameters:
hDS handle to the datasource
iLayer the index of the layer to delete.
Returns:
OGRERR_NONE on success, or OGRERR_UNSUPPORTED_OPERATION if deleting layers is not supported for this datasource.
void OGR_DS_Destroy ( OGRDataSourceH  hDataSource  ) 

Closes opened datasource and releases allocated resources.

This method is the same as the C++ method OGRDataSource::DestroyDataSource().

Deprecated:
Use GDALClose() in GDAL 2.0
Parameters:
hDataSource handle to allocated datasource object.
OGRLayerH OGR_DS_ExecuteSQL ( OGRDataSourceH  hDS,
const char *  pszSQLCommand,
OGRGeometryH  hSpatialFilter,
const char *  pszDialect 
)

Execute an SQL statement against the data store.

The result of an SQL query is either NULL for statements that are in error, or that have no results set, or an OGRLayer handle representing a results set from the query. Note that this OGRLayer is in addition to the layers in the data store and must be destroyed with OGR_DS_ReleaseResultSet() before the data source is closed (destroyed).

For more information on the SQL dialect supported internally by OGR review the OGR SQL document. Some drivers (ie. Oracle and PostGIS) pass the SQL directly through to the underlying RDBMS.

Starting with OGR 1.10, the SQLITE dialect can also be used.

Deprecated:
Use GDALDatasetExecuteSQL() in GDAL 2.0
Parameters:
hDS handle to the data source on which the SQL query is executed.
pszSQLCommand the SQL statement to execute.
hSpatialFilter handle to a geometry which represents a spatial filter. Can be NULL.
pszDialect allows control of the statement dialect. If set to NULL, the OGR SQL engine will be used, except for RDBMS drivers that will use their dedicated SQL engine, unless OGRSQL is explicitly passed as the dialect. Starting with OGR 1.10, the SQLITE dialect can also be used.
Returns:
an handle to a OGRLayer containing the results of the query. Deallocate with OGR_DS_ReleaseResultSet().
OGRSFDriverH OGR_DS_GetDriver ( OGRDataSourceH  hDS  ) 

Returns the driver that the dataset was opened with.

Deprecated:
Use GDALGetDatasetDriver() in GDAL 2.0
Parameters:
hDS handle to the datasource
Returns:
NULL if driver info is not available, or pointer to a driver owned by the OGRSFDriverManager.
OGRLayerH OGR_DS_GetLayer ( OGRDataSourceH  hDS,
int  iLayer 
)

Fetch a layer by index.

The returned layer remains owned by the OGRDataSource and should not be deleted by the application.

Deprecated:
Use GDALDatasetGetLayer() in GDAL 2.0
Parameters:
hDS handle to the data source from which to get the layer.
iLayer a layer number between 0 and OGR_DS_GetLayerCount()-1.
Returns:
an handle to the layer, or NULL if iLayer is out of range or an error occurs.
OGRLayerH OGR_DS_GetLayerByName ( OGRDataSourceH  hDS,
const char *  pszLayerName 
)

Fetch a layer by name.

The returned layer remains owned by the OGRDataSource and should not be deleted by the application.

Deprecated:
Use GDALDatasetGetLayerByName() in GDAL 2.0
Parameters:
hDS handle to the data source from which to get the layer.
pszLayerName Layer the layer name of the layer to fetch.
Returns:
an handle to the layer, or NULL if the layer is not found or an error occurs.
int OGR_DS_GetLayerCount ( OGRDataSourceH  hDS  ) 

Get the number of layers in this data source.

Deprecated:
Use GDALDatasetGetLayerCount() in GDAL 2.0
Parameters:
hDS handle to the data source from which to get the number of layers.
Returns:
layer count.
const char * OGR_DS_GetName ( OGRDataSourceH  hDS  ) 

Returns the name of the data source.

This string should be sufficient to open the data source if passed to the same OGRSFDriver that this data source was opened with, but it need not be exactly the same string that was used to open the data source. Normally this is a filename.

Deprecated:
Use GDALGetDescription() in GDAL 2.0
Parameters:
hDS handle to the data source to get the name from.
Returns:
pointer to an internal name string which should not be modified or freed by the caller.
void OGR_DS_ReleaseResultSet ( OGRDataSourceH  hDS,
OGRLayerH  hLayer 
)

Release results of OGR_DS_ExecuteSQL().

This function should only be used to deallocate OGRLayers resulting from an OGR_DS_ExecuteSQL() call on the same OGRDataSource. Failure to deallocate a results set before destroying the OGRDataSource may cause errors.

Deprecated:
Use GDALDatasetReleaseResultSet() in GDAL 2.0
Parameters:
hDS an handle to the data source on which was executed an SQL query.
hLayer handle to the result of a previous OGR_DS_ExecuteSQL() call.
int OGR_DS_TestCapability ( OGRDataSourceH  hDS,
const char *  pszCapability 
)

Test if capability is available.

One of the following data source capability names can be passed into this function, and a TRUE or FALSE value will be returned indicating whether or not the capability is available for this object.

  • ODsCCreateLayer: True if this datasource can create new layers.
  • ODsCDeleteLayer: True if this datasource can delete existing layers.

  • ODsCCreateGeomFieldAfterCreateLayer: True if the layers of this datasource support CreateGeomField() just after layer creation.

  • ODsCCurveGeometries: True if this datasource supports writing curve geometries. (GDAL 2.0). In that case, OLCCurveGeometries must also be declared in layers of that dataset.

The #define macro forms of the capability names should be used in preference to the strings themselves to avoid mispelling.

Deprecated:
Use GDALDatasetTestCapability() in GDAL 2.0
Parameters:
hDS handle to the data source against which to test the capability.
pszCapability the capability to test.
Returns:
TRUE if capability available otherwise FALSE.
OGRFeatureH OGR_F_Clone ( OGRFeatureH  hFeat  ) 

Duplicate feature.

The newly created feature is owned by the caller, and will have it's own reference to the OGRFeatureDefn.

This function is the same as the C++ method OGRFeature::Clone().

Parameters:
hFeat handle to the feature to clone.
Returns:
an handle to the new feature, exactly matching this feature.
OGRFeatureH OGR_F_Create ( OGRFeatureDefnH  hDefn  ) 

Feature factory.

Note that the OGRFeature will increment the reference count of it's defining OGRFeatureDefn. Destruction of the OGRFeatureDefn before destruction of all OGRFeatures that depend on it is likely to result in a crash.

This function is the same as the C++ method OGRFeature::OGRFeature().

Parameters:
hDefn handle to the feature class (layer) definition to which the feature will adhere.
Returns:
an handle to the new feature object with null fields and no geometry.
void OGR_F_Destroy ( OGRFeatureH  hFeat  ) 

Destroy feature.

The feature is deleted, but within the context of the GDAL/OGR heap. This is necessary when higher level applications use GDAL/OGR from a DLL and they want to delete a feature created within the DLL. If the delete is done in the calling application the memory will be freed onto the application heap which is inappropriate.

This function is the same as the C++ method OGRFeature::DestroyFeature().

Parameters:
hFeat handle to the feature to destroy.
void OGR_F_DumpReadable ( OGRFeatureH  hFeat,
FILE *  fpOut 
)

Dump this feature in a human readable form.

This dumps the attributes, and geometry; however, it doesn't definition information (other than field types and names), nor does it report the geometry spatial reference system.

This function is the same as the C++ method OGRFeature::DumpReadable().

Parameters:
hFeat handle to the feature to dump.
fpOut the stream to write to, such as strout.
int OGR_F_Equal ( OGRFeatureH  hFeat,
OGRFeatureH  hOtherFeat 
)

Test if two features are the same.

Two features are considered equal if the share them (handle equality) same OGRFeatureDefn, have the same field values, and the same geometry (as tested by OGR_G_Equal()) as well as the same feature id.

This function is the same as the C++ method OGRFeature::Equal().

Parameters:
hFeat handle to one of the feature.
hOtherFeat handle to the other feature to test this one against.
Returns:
TRUE if they are equal, otherwise FALSE.
OGRFeatureDefnH OGR_F_GetDefnRef ( OGRFeatureH  hFeat  ) 

Fetch feature definition.

This function is the same as the C++ method OGRFeature::GetDefnRef().

Parameters:
hFeat handle to the feature to get the feature definition from.
Returns:
an handle to the feature definition object on which feature depends.
long OGR_F_GetFID ( OGRFeatureH  hFeat  ) 

Get feature identifier.

This function is the same as the C++ method OGRFeature::GetFID().

Parameters:
hFeat handle to the feature from which to get the feature identifier.
Returns:
feature id or OGRNullFID if none has been assigned.
GByte* OGR_F_GetFieldAsBinary ( OGRFeatureH  hFeat,
int  iField,
int *  pnBytes 
)

Fetch field value as binary.

Currently this method only works for OFTBinary fields.

This function is the same as the C++ method OGRFeature::GetFieldAsBinary().

Parameters:
hFeat handle to the feature that owned the field.
iField the field to fetch, from 0 to GetFieldCount()-1.
pnBytes location to place count of bytes returned.
Returns:
the field value. This list is internal, and should not be modified, or freed. Its lifetime may be very brief.
int OGR_F_GetFieldAsDateTime ( OGRFeatureH  hFeat,
int  iField,
int *  pnYear,
int *  pnMonth,
int *  pnDay,
int *  pnHour,
int *  pnMinute,
int *  pnSecond,
int *  pnTZFlag 
)

Fetch field value as date and time.

Currently this method only works for OFTDate, OFTTime and OFTDateTime fields.

This function is the same as the C++ method OGRFeature::GetFieldAsDateTime().

Parameters:
hFeat handle to the feature that owned the field.
iField the field to fetch, from 0 to GetFieldCount()-1.
pnYear (including century)
pnMonth (1-12)
pnDay (1-31)
pnHour (0-23)
pnMinute (0-59)
pnSecond (0-59)
pnTZFlag (0=unknown, 1=localtime, 100=GMT, see data model for details)
Returns:
TRUE on success or FALSE on failure.
double OGR_F_GetFieldAsDouble ( OGRFeatureH  hFeat,
int  iField 
)

Fetch field value as a double.

OFTString features will be translated using CPLAtof(). OFTInteger fields will be cast to double. Other field types, or errors will result in a return value of zero.

This function is the same as the C++ method OGRFeature::GetFieldAsDouble().

Parameters:
hFeat handle to the feature that owned the field.
iField the field to fetch, from 0 to GetFieldCount()-1.
Returns:
the field value.
const double* OGR_F_GetFieldAsDoubleList ( OGRFeatureH  hFeat,
int  iField,
int *  pnCount 
)

Fetch field value as a list of doubles.

Currently this function only works for OFTRealList fields.

This function is the same as the C++ method OGRFeature::GetFieldAsDoubleList().

Parameters:
hFeat handle to the feature that owned the field.
iField the field to fetch, from 0 to GetFieldCount()-1.
pnCount an integer to put the list count (number of doubles) into.
Returns:
the field value. This list is internal, and should not be modified, or freed. Its lifetime may be very brief. If *pnCount is zero on return the returned pointer may be NULL or non-NULL.
int OGR_F_GetFieldAsInteger ( OGRFeatureH  hFeat,
int  iField 
)

Fetch field value as integer.

OFTString features will be translated using atoi(). OFTReal fields will be cast to integer. Other field types, or errors will result in a return value of zero.

This function is the same as the C++ method OGRFeature::GetFieldAsInteger().

Parameters:
hFeat handle to the feature that owned the field.
iField the field to fetch, from 0 to GetFieldCount()-1.
Returns:
the field value.
const int* OGR_F_GetFieldAsIntegerList ( OGRFeatureH  hFeat,
int  iField,
int *  pnCount 
)

Fetch field value as a list of integers.

Currently this function only works for OFTIntegerList fields.

This function is the same as the C++ method OGRFeature::GetFieldAsIntegerList().

Parameters:
hFeat handle to the feature that owned the field.
iField the field to fetch, from 0 to GetFieldCount()-1.
pnCount an integer to put the list count (number of integers) into.
Returns:
the field value. This list is internal, and should not be modified, or freed. Its lifetime may be very brief. If *pnCount is zero on return the returned pointer may be NULL or non-NULL.
const char* OGR_F_GetFieldAsString ( OGRFeatureH  hFeat,
int  iField 
)

Fetch field value as a string.

OFTReal and OFTInteger fields will be translated to string using sprintf(), but not necessarily using the established formatting rules. Other field types, or errors will result in a return value of zero.

This function is the same as the C++ method OGRFeature::GetFieldAsString().

Parameters:
hFeat handle to the feature that owned the field.
iField the field to fetch, from 0 to GetFieldCount()-1.
Returns:
the field value. This string is internal, and should not be modified, or freed. Its lifetime may be very brief.
char** OGR_F_GetFieldAsStringList ( OGRFeatureH  hFeat,
int  iField 
)

Fetch field value as a list of strings.

Currently this method only works for OFTStringList fields.

The returned list is terminated by a NULL pointer. The number of elements can also be calculated using CSLCount().

This function is the same as the C++ method OGRFeature::GetFieldAsStringList().

Parameters:
hFeat handle to the feature that owned the field.
iField the field to fetch, from 0 to GetFieldCount()-1.
Returns:
the field value. This list is internal, and should not be modified, or freed. Its lifetime may be very brief.
int OGR_F_GetFieldCount ( OGRFeatureH  hFeat  ) 

Fetch number of fields on this feature This will always be the same as the field count for the OGRFeatureDefn.

This function is the same as the C++ method OGRFeature::GetFieldCount().

Parameters:
hFeat handle to the feature to get the fields count from.
Returns:
count of fields.
OGRFieldDefnH OGR_F_GetFieldDefnRef ( OGRFeatureH  hFeat,
int  i 
)

Fetch definition for this field.

This function is the same as the C++ method OGRFeature::GetFieldDefnRef().

Parameters:
hFeat handle to the feature on which the field is found.
i the field to fetch, from 0 to GetFieldCount()-1.
Returns:
an handle to the field definition (from the OGRFeatureDefn). This is an internal reference, and should not be deleted or modified.
int OGR_F_GetFieldIndex ( OGRFeatureH  hFeat,
const char *  pszName 
)

Fetch the field index given field name.

This is a cover for the OGRFeatureDefn::GetFieldIndex() method.

This function is the same as the C++ method OGRFeature::GetFieldIndex().

Parameters:
hFeat handle to the feature on which the field is found.
pszName the name of the field to search for.
Returns:
the field index, or -1 if no matching field is found.
OGRGeometryH OGR_F_GetGeometryRef ( OGRFeatureH  hFeat  ) 

Fetch an handle to feature geometry.

This function is the same as the C++ method OGRFeature::GetGeometryRef().

Parameters:
hFeat handle to the feature to get geometry from.
Returns:
an handle to internal feature geometry. This object should not be modified.
int OGR_F_GetGeomFieldCount ( OGRFeatureH  hFeat  ) 

Fetch number of geometry fields on this feature This will always be the same as the geometry field count for the OGRFeatureDefn.

This function is the same as the C++ method OGRFeature::GetGeomFieldCount().

Parameters:
hFeat handle to the feature to get the geometry fields count from.
Returns:
count of geometry fields.
Since:
GDAL 1.11
OGRGeomFieldDefnH OGR_F_GetGeomFieldDefnRef ( OGRFeatureH  hFeat,
int  i 
)

Fetch definition for this geometry field.

This function is the same as the C++ method OGRFeature::GetGeomFieldDefnRef().

Parameters:
hFeat handle to the feature on which the field is found.
i the field to fetch, from 0 to GetGeomFieldCount()-1.
Returns:
an handle to the field definition (from the OGRFeatureDefn). This is an internal reference, and should not be deleted or modified.
Since:
GDAL 1.11
int OGR_F_GetGeomFieldIndex ( OGRFeatureH  hFeat,
const char *  pszName 
)

Fetch the geometry field index given geometry field name.

This is a cover for the OGRFeatureDefn::GetGeomFieldIndex() method.

This function is the same as the C++ method OGRFeature::GetGeomFieldIndex().

Parameters:
hFeat handle to the feature on which the geometry field is found.
pszName the name of the geometry field to search for.
Returns:
the geometry field index, or -1 if no matching geometry field is found.
Since:
GDAL 1.11
OGRGeometryH OGR_F_GetGeomFieldRef ( OGRFeatureH  hFeat,
int  iField 
)

Fetch an handle to feature geometry.

This function is the same as the C++ method OGRFeature::GetGeomFieldRef().

Parameters:
hFeat handle to the feature to get geometry from.
iField geometry field to get.
Returns:
an handle to internal feature geometry. This object should not be modified.
Since:
GDAL 1.11
OGRField* OGR_F_GetRawFieldRef ( OGRFeatureH  hFeat,
int  iField 
)

Fetch an handle to the internal field value given the index.

This function is the same as the C++ method OGRFeature::GetRawFieldRef().

Parameters:
hFeat handle to the feature on which field is found.
iField the field to fetch, from 0 to GetFieldCount()-1.
Returns:
the returned handle is to an internal data structure, and should not be freed, or modified.
const char* OGR_F_GetStyleString ( OGRFeatureH  hFeat  ) 

Fetch style string for this feature.

Set the OGR Feature Style Specification for details on the format of this string, and ogr_featurestyle.h for services available to parse it.

This function is the same as the C++ method OGRFeature::GetStyleString().

Parameters:
hFeat handle to the feature to get the style from.
Returns:
a reference to a representation in string format, or NULL if there isn't one.
int OGR_F_IsFieldSet ( OGRFeatureH  hFeat,
int  iField 
)

Test if a field has ever been assigned a value or not.

This function is the same as the C++ method OGRFeature::IsFieldSet().

Parameters:
hFeat handle to the feature on which the field is.
iField the field to test.
Returns:
TRUE if the field has been set, otherwise false.
OGRErr OGR_F_SetFID ( OGRFeatureH  hFeat,
long  nFID 
)

Set the feature identifier.

For specific types of features this operation may fail on illegal features ids. Generally it always succeeds. Feature ids should be greater than or equal to zero, with the exception of OGRNullFID (-1) indicating that the feature id is unknown.

This function is the same as the C++ method OGRFeature::SetFID().

Parameters:
hFeat handle to the feature to set the feature id to.
nFID the new feature identifier value to assign.
Returns:
On success OGRERR_NONE, or on failure some other value.
void OGR_F_SetFieldBinary ( OGRFeatureH  hFeat,
int  iField,
int  nBytes,
GByte *  pabyData 
)

Set field to binary data.

This function currently on has an effect of OFTBinary fields.

This function is the same as the C++ method OGRFeature::SetField().

Parameters:
hFeat handle to the feature that owned the field.
iField the field to set, from 0 to GetFieldCount()-1.
nBytes the number of bytes in pabyData array.
pabyData the data to apply.
void OGR_F_SetFieldDateTime ( OGRFeatureH  hFeat,
int  iField,
int  nYear,
int  nMonth,
int  nDay,
int  nHour,
int  nMinute,
int  nSecond,
int  nTZFlag 
)

Set field to datetime.

This method currently only has an effect for OFTDate, OFTTime and OFTDateTime fields.

Parameters:
hFeat handle to the feature that owned the field.
iField the field to set, from 0 to GetFieldCount()-1.
nYear (including century)
nMonth (1-12)
nDay (1-31)
nHour (0-23)
nMinute (0-59)
nSecond (0-59)
nTZFlag (0=unknown, 1=localtime, 100=GMT, see data model for details)
void OGR_F_SetFieldDouble ( OGRFeatureH  hFeat,
int  iField,
double  dfValue 
)

Set field to double value.

OFTInteger and OFTReal fields will be set directly. OFTString fields will be assigned a string representation of the value, but not necessarily taking into account formatting constraints on this field. Other field types may be unaffected.

This function is the same as the C++ method OGRFeature::SetField().

Parameters:
hFeat handle to the feature that owned the field.
iField the field to fetch, from 0 to GetFieldCount()-1.
dfValue the value to assign.
void OGR_F_SetFieldDoubleList ( OGRFeatureH  hFeat,
int  iField,
int  nCount,
double *  padfValues 
)

Set field to list of doubles value.

This function currently on has an effect of OFTRealList fields.

This function is the same as the C++ method OGRFeature::SetField().

Parameters:
hFeat handle to the feature that owned the field.
iField the field to set, from 0 to GetFieldCount()-1.
nCount the number of values in the list being assigned.
padfValues the values to assign.
void OGR_F_SetFieldInteger ( OGRFeatureH  hFeat,
int  iField,
int  nValue 
)

Set field to integer value.

OFTInteger and OFTReal fields will be set directly. OFTString fields will be assigned a string representation of the value, but not necessarily taking into account formatting constraints on this field. Other field types may be unaffected.

This function is the same as the C++ method OGRFeature::SetField().

Parameters:
hFeat handle to the feature that owned the field.
iField the field to fetch, from 0 to GetFieldCount()-1.
nValue the value to assign.
void OGR_F_SetFieldIntegerList ( OGRFeatureH  hFeat,
int  iField,
int  nCount,
int *  panValues 
)

Set field to list of integers value.

This function currently on has an effect of OFTIntegerList fields.

This function is the same as the C++ method OGRFeature::SetField().

Parameters:
hFeat handle to the feature that owned the field.
iField the field to set, from 0 to GetFieldCount()-1.
nCount the number of values in the list being assigned.
panValues the values to assign.
void OGR_F_SetFieldRaw ( OGRFeatureH  hFeat,
int  iField,
OGRField psValue 
)

Set field.

The passed value OGRField must be of exactly the same type as the target field, or an application crash may occur. The passed value is copied, and will not be affected. It remains the responsibility of the caller.

This function is the same as the C++ method OGRFeature::SetField().

Parameters:
hFeat handle to the feature that owned the field.
iField the field to fetch, from 0 to GetFieldCount()-1.
psValue handle on the value to assign.
void OGR_F_SetFieldString ( OGRFeatureH  hFeat,
int  iField,
const char *  pszValue 
)

Set field to string value.

OFTInteger fields will be set based on an atoi() conversion of the string. OFTReal fields will be set based on an CPLAtof() conversion of the string. Other field types may be unaffected.

This function is the same as the C++ method OGRFeature::SetField().

Parameters:
hFeat handle to the feature that owned the field.
iField the field to fetch, from 0 to GetFieldCount()-1.
pszValue the value to assign.
void OGR_F_SetFieldStringList ( OGRFeatureH  hFeat,
int  iField,
char **  papszValues 
)

Set field to list of strings value.

This function currently on has an effect of OFTStringList fields.

This function is the same as the C++ method OGRFeature::SetField().

Parameters:
hFeat handle to the feature that owned the field.
iField the field to set, from 0 to GetFieldCount()-1.
papszValues the values to assign.
OGRErr OGR_F_SetFrom ( OGRFeatureH  hFeat,
OGRFeatureH  hOtherFeat,
int  bForgiving 
)

Set one feature from another.

Overwrite the contents of this feature from the geometry and attributes of another. The hOtherFeature does not need to have the same OGRFeatureDefn. Field values are copied by corresponding field names. Field types do not have to exactly match. OGR_F_SetField*() function conversion rules will be applied as needed.

This function is the same as the C++ method OGRFeature::SetFrom().

Parameters:
hFeat handle to the feature to set to.
hOtherFeat handle to the feature from which geometry, and field values will be copied.
bForgiving TRUE if the operation should continue despite lacking output fields matching some of the source fields.
Returns:
OGRERR_NONE if the operation succeeds, even if some values are not transferred, otherwise an error code.
OGRErr OGR_F_SetFromWithMap ( OGRFeatureH  hFeat,
OGRFeatureH  hOtherFeat,
int  bForgiving,
int *  panMap 
)

Set one feature from another.

Overwrite the contents of this feature from the geometry and attributes of another. The hOtherFeature does not need to have the same OGRFeatureDefn. Field values are copied according to the provided indices map. Field types do not have to exactly match. OGR_F_SetField*() function conversion rules will be applied as needed. This is more efficient than OGR_F_SetFrom() in that this doesn't lookup the fields by their names. Particularly useful when the field names don't match.

This function is the same as the C++ method OGRFeature::SetFrom().

Parameters:
hFeat handle to the feature to set to.
hOtherFeat handle to the feature from which geometry, and field values will be copied.
panMap Array of the indices of the destination feature's fields stored at the corresponding index of the source feature's fields. A value of -1 should be used to ignore the source's field. The array should not be NULL and be as long as the number of fields in the source feature.
bForgiving TRUE if the operation should continue despite lacking output fields matching some of the source fields.
Returns:
OGRERR_NONE if the operation succeeds, even if some values are not transferred, otherwise an error code.
OGRErr OGR_F_SetGeometry ( OGRFeatureH  hFeat,
OGRGeometryH  hGeom 
)

Set feature geometry.

This function updates the features geometry, and operate exactly as SetGeometryDirectly(), except that this function does not assume ownership of the passed geometry, but instead makes a copy of it.

This function is the same as the C++ OGRFeature::SetGeometry().

Parameters:
hFeat handle to the feature on which new geometry is applied to.
hGeom handle to the new geometry to apply to feature.
Returns:
OGRERR_NONE if successful, or OGR_UNSUPPORTED_GEOMETRY_TYPE if the geometry type is illegal for the OGRFeatureDefn (checking not yet implemented).
OGRErr OGR_F_SetGeometryDirectly ( OGRFeatureH  hFeat,
OGRGeometryH  hGeom 
)

Set feature geometry.

This function updates the features geometry, and operate exactly as SetGeometry(), except that this function assumes ownership of the passed geometry (even in case of failure of that function).

This function is the same as the C++ method OGRFeature::SetGeometryDirectly.

Parameters:
hFeat handle to the feature on which to apply the geometry.
hGeom handle to the new geometry to apply to feature.
Returns:
OGRERR_NONE if successful, or OGR_UNSUPPORTED_GEOMETRY_TYPE if the geometry type is illegal for the OGRFeatureDefn (checking not yet implemented).
OGRErr OGR_F_SetGeomField ( OGRFeatureH  hFeat,
int  iField,
OGRGeometryH  hGeom 
)

Set feature geometry of a specified geometry field.

This function updates the features geometry, and operate exactly as SetGeometryDirectly(), except that this function does not assume ownership of the passed geometry, but instead makes a copy of it.

This function is the same as the C++ OGRFeature::SetGeomField().

Parameters:
hFeat handle to the feature on which new geometry is applied to.
iField geometry field to set.
hGeom handle to the new geometry to apply to feature.
Returns:
OGRERR_NONE if successful, or OGR_UNSUPPORTED_GEOMETRY_TYPE if the geometry type is illegal for the OGRFeatureDefn (checking not yet implemented).
OGRErr OGR_F_SetGeomFieldDirectly ( OGRFeatureH  hFeat,
int  iField,
OGRGeometryH  hGeom 
)

Set feature geometry of a specified geometry field.

This function updates the features geometry, and operate exactly as SetGeomField(), except that this function assumes ownership of the passed geometry (even in case of failure of that function).

This function is the same as the C++ method OGRFeature::SetGeomFieldDirectly.

Parameters:
hFeat handle to the feature on which to apply the geometry.
iField geometry field to set.
hGeom handle to the new geometry to apply to feature.
Returns:
OGRERR_NONE if successful, or OGRERR_FAILURE if the index is invalid, or OGR_UNSUPPORTED_GEOMETRY_TYPE if the geometry type is illegal for the OGRFeatureDefn (checking not yet implemented).
Since:
GDAL 1.11
void OGR_F_SetStyleString ( OGRFeatureH  hFeat,
const char *  pszStyle 
)

Set feature style string.

This method operate exactly as OGR_F_SetStyleStringDirectly() except that it does not assume ownership of the passed string, but instead makes a copy of it.

This function is the same as the C++ method OGRFeature::SetStyleString().

Parameters:
hFeat handle to the feature to set style to.
pszStyle the style string to apply to this feature, cannot be NULL.
void OGR_F_SetStyleStringDirectly ( OGRFeatureH  hFeat,
char *  pszStyle 
)

Set feature style string.

This method operate exactly as OGR_F_SetStyleString() except that it assumes ownership of the passed string.

This function is the same as the C++ method OGRFeature::SetStyleStringDirectly().

Parameters:
hFeat handle to the feature to set style to.
pszStyle the style string to apply to this feature, cannot be NULL.
OGRGeometryH OGR_F_StealGeometry ( OGRFeatureH  hFeat  ) 

Take away ownership of geometry.

Fetch the geometry from this feature, and clear the reference to the geometry on the feature. This is a mechanism for the application to take over ownship of the geometry from the feature without copying. Sort of an inverse to OGR_FSetGeometryDirectly().

After this call the OGRFeature will have a NULL geometry.

Returns:
the pointer to the geometry.
void OGR_F_UnsetField ( OGRFeatureH  hFeat,
int  iField 
)

Clear a field, marking it as unset.

This function is the same as the C++ method OGRFeature::UnsetField().

Parameters:
hFeat handle to the feature on which the field is.
iField the field to unset.
void OGR_FD_AddFieldDefn ( OGRFeatureDefnH  hDefn,
OGRFieldDefnH  hNewField 
)

Add a new field definition to the passed feature definition.

To add a new field definition to a layer definition, do not use this function directly, but use OGR_L_CreateField() instead.

This function should only be called while there are no OGRFeature objects in existance based on this OGRFeatureDefn. The OGRFieldDefn passed in is copied, and remains the responsibility of the caller.

This function is the same as the C++ method OGRFeatureDefn::AddFieldDefn().

Parameters:
hDefn handle to the feature definition to add the field definition to.
hNewField handle to the new field definition.
void OGR_FD_AddGeomFieldDefn ( OGRFeatureDefnH  hDefn,
OGRGeomFieldDefnH  hNewGeomField 
)

Add a new field definition to the passed feature definition.

To add a new field definition to a layer definition, do not use this function directly, but use OGR_L_CreateGeomField() instead.

This function should only be called while there are no OGRFeature objects in existance based on this OGRFeatureDefn. The OGRGeomFieldDefn passed in is copied, and remains the responsibility of the caller.

This function is the same as the C++ method OGRFeatureDefn::AddGeomFieldDefn().

Parameters:
hDefn handle to the feature definition to add the geometry field definition to.
hNewGeomField handle to the new field definition.
Since:
GDAL 1.11
OGRFeatureDefnH OGR_FD_Create ( const char *  pszName  ) 

Create a new feature definition object to hold the field definitions.

The OGRFeatureDefn maintains a reference count, but this starts at zero, and should normally be incremented by the owner.

This function is the same as the C++ method OGRFeatureDefn::OGRFeatureDefn().

Parameters:
pszName the name to be assigned to this layer/class. It does not need to be unique.
Returns:
handle to the newly created feature definition.
OGRErr OGR_FD_DeleteFieldDefn ( OGRFeatureDefnH  hDefn,
int  iField 
)

Delete an existing field definition.

To delete an existing field definition from a layer definition, do not use this function directly, but use OGR_L_DeleteField() instead.

This method should only be called while there are no OGRFeature objects in existance based on this OGRFeatureDefn.

This method is the same as the C++ method OGRFeatureDefn::DeleteFieldDefn().

Parameters:
hDefn handle to the feature definition.
iField the index of the field defintion.
Returns:
OGRERR_NONE in case of success.
Since:
OGR 1.9.0
OGRErr OGR_FD_DeleteGeomFieldDefn ( OGRFeatureDefnH  hDefn,
int  iGeomField 
)

Delete an existing geometry field definition.

To delete an existing geometry field definition from a layer definition, do not use this function directly, but use OGR_L_DeleteGeomField() instead (*not implemented yet*)

This method should only be called while there are no OGRFeature objects in existance based on this OGRFeatureDefn.

This method is the same as the C++ method OGRFeatureDefn::DeleteGeomFieldDefn().

Parameters:
hDefn handle to the feature definition.
iGeomField the index of the geometry field defintion.
Returns:
OGRERR_NONE in case of success.
Since:
GDAL 1.11
int OGR_FD_Dereference ( OGRFeatureDefnH  hDefn  ) 

Decrements the reference count by one.

This function is the same as the C++ method OGRFeatureDefn::Dereference().

Parameters:
hDefn handle to the feature definition on witch OGRFeature are based on.
Returns:
the updated reference count.
void OGR_FD_Destroy ( OGRFeatureDefnH  hDefn  ) 

Destroy a feature definition object and release all memory associated with it.

This function is the same as the C++ method OGRFeatureDefn::~OGRFeatureDefn().

Parameters:
hDefn handle to the feature definition to be destroyed.
int OGR_FD_GetFieldCount ( OGRFeatureDefnH  hDefn  ) 

Fetch number of fields on the passed feature definition.

This function is the same as the C++ OGRFeatureDefn::GetFieldCount().

Parameters:
hDefn handle to the feature definition to get the fields count from.
Returns:
count of fields.
OGRFieldDefnH OGR_FD_GetFieldDefn ( OGRFeatureDefnH  hDefn,
int  iField 
)

Fetch field definition of the passed feature definition.

This function is the same as the C++ method OGRFeatureDefn::GetFieldDefn().

Starting with GDAL 1.7.0, this method will also issue an error if the index is not valid.

Parameters:
hDefn handle to the feature definition to get the field definition from.
iField the field to fetch, between 0 and GetFieldCount()-1.
Returns:
an handle to an internal field definition object or NULL if invalid index. This object should not be modified or freed by the application.
int OGR_FD_GetFieldIndex ( OGRFeatureDefnH  hDefn,
const char *  pszFieldName 
)

Find field by name.

The field index of the first field matching the passed field name (case insensitively) is returned.

This function is the same as the C++ method OGRFeatureDefn::GetFieldIndex.

Parameters:
hDefn handle to the feature definition to get field index from.
pszFieldName the field name to search for.
Returns:
the field index, or -1 if no match found.
int OGR_FD_GetGeomFieldCount ( OGRFeatureDefnH  hDefn  ) 

Fetch number of geometry fields on the passed feature definition.

This function is the same as the C++ OGRFeatureDefn::GetGeomFieldCount().

Parameters:
hDefn handle to the feature definition to get the fields count from.
Returns:
count of geometry fields.
Since:
GDAL 1.11
OGRGeomFieldDefnH OGR_FD_GetGeomFieldDefn ( OGRFeatureDefnH  hDefn,
int  iGeomField 
)

Fetch geometry field definition of the passed feature definition.

This function is the same as the C++ method OGRFeatureDefn::GetGeomFieldDefn().

Parameters:
hDefn handle to the feature definition to get the field definition from.
iGeomField the geometry field to fetch, between 0 and GetGeomFieldCount()-1.
Returns:
an handle to an internal field definition object or NULL if invalid index. This object should not be modified or freed by the application.
Since:
GDAL 1.11
int OGR_FD_GetGeomFieldIndex ( OGRFeatureDefnH  hDefn,
const char *  pszGeomFieldName 
)

Find geometry field by name.

The geometry field index of the first geometry field matching the passed field name (case insensitively) is returned.

This function is the same as the C++ method OGRFeatureDefn::GetGeomFieldIndex.

Parameters:
hDefn handle to the feature definition to get field index from.
pszGeomFieldName the geometry field name to search for.
Returns:
the geometry field index, or -1 if no match found.
OGRwkbGeometryType OGR_FD_GetGeomType ( OGRFeatureDefnH  hDefn  ) 

Fetch the geometry base type of the passed feature definition.

This function is the same as the C++ method OGRFeatureDefn::GetGeomType().

Starting with GDAL 1.11, this method returns GetGeomFieldDefn(0)->GetType().

Parameters:
hDefn handle to the feature definition to get the geometry type from.
Returns:
the base type for all geometry related to this definition.
const char* OGR_FD_GetName ( OGRFeatureDefnH  hDefn  ) 

Get name of the OGRFeatureDefn passed as an argument.

This function is the same as the C++ method OGRFeatureDefn::GetName().

Parameters:
hDefn handle to the feature definition to get the name from.
Returns:
the name. This name is internal and should not be modified, or freed.
int OGR_FD_GetReferenceCount ( OGRFeatureDefnH  hDefn  ) 

Fetch current reference count.

This function is the same as the C++ method OGRFeatureDefn::GetReferenceCount().

Parameters:
hDefn handle to the feature definition on witch OGRFeature are based on.
Returns:
the current reference count.
int OGR_FD_IsGeometryIgnored ( OGRFeatureDefnH  hDefn  ) 

Determine whether the geometry can be omitted when fetching features.

This function is the same as the C++ method OGRFeatureDefn::IsGeometryIgnored().

Starting with GDAL 1.11, this method returns GetGeomFieldDefn(0)->IsIgnored().

Parameters:
hDefn handle to the feature definition on witch OGRFeature are based on.
Returns:
ignore state
int OGR_FD_IsSame ( OGRFeatureDefnH  hFDefn,
OGRFeatureDefnH  hOtherFDefn 
)

Test if the feature definition is identical to the other one.

Parameters:
hFDefn handle to the feature definition on witch OGRFeature are based on.
hOtherFDefn handle to the other feature definition to compare to.
Returns:
TRUE if the feature definition is identical to the other one.
Since:
OGR 1.11
int OGR_FD_IsStyleIgnored ( OGRFeatureDefnH  hDefn  ) 

Determine whether the style can be omitted when fetching features.

This function is the same as the C++ method OGRFeatureDefn::IsStyleIgnored().

Parameters:
hDefn handle to the feature definition on which OGRFeature are based on.
Returns:
ignore state
int OGR_FD_Reference ( OGRFeatureDefnH  hDefn  ) 

Increments the reference count by one.

The reference count is used keep track of the number of OGRFeature objects referencing this definition.

This function is the same as the C++ method OGRFeatureDefn::Reference().

Parameters:
hDefn handle to the feature definition on witch OGRFeature are based on.
Returns:
the updated reference count.
void OGR_FD_Release ( OGRFeatureDefnH  hDefn  ) 

Drop a reference, and destroy if unreferenced.

This function is the same as the C++ method OGRFeatureDefn::Release().

Parameters:
hDefn handle to the feature definition to be released.
void OGR_FD_SetGeometryIgnored ( OGRFeatureDefnH  hDefn,
int  bIgnore 
)

Set whether the geometry can be omitted when fetching features.

This function is the same as the C++ method OGRFeatureDefn::SetGeometryIgnored().

Starting with GDAL 1.11, this method calls GetGeomFieldDefn(0)->SetIgnored().

Parameters:
hDefn handle to the feature definition on witch OGRFeature are based on.
bIgnore ignore state
void OGR_FD_SetGeomType ( OGRFeatureDefnH  hDefn,
OGRwkbGeometryType  eType 
)

Assign the base geometry type for the passed layer (the same as the feature definition).

All geometry objects using this type must be of the defined type or a derived type. The default upon creation is wkbUnknown which allows for any geometry type. The geometry type should generally not be changed after any OGRFeatures have been created against this definition.

This function is the same as the C++ method OGRFeatureDefn::SetGeomType().

Starting with GDAL 1.11, this method calls GetGeomFieldDefn(0)->SetType().

Parameters:
hDefn handle to the layer or feature definition to set the geometry type to.
eType the new type to assign.
void OGR_FD_SetStyleIgnored ( OGRFeatureDefnH  hDefn,
int  bIgnore 
)

Set whether the style can be omitted when fetching features.

This function is the same as the C++ method OGRFeatureDefn::SetStyleIgnored().

Parameters:
hDefn handle to the feature definition on witch OGRFeature are based on.
bIgnore ignore state
OGRFieldDefnH OGR_Fld_Create ( const char *  pszName,
OGRFieldType  eType 
)

Create a new field definition.

This function is the same as the CPP method OGRFieldDefn::OGRFieldDefn().

Parameters:
pszName the name of the new field definition.
eType the type of the new field definition.
Returns:
handle to the new field definition.
void OGR_Fld_Destroy ( OGRFieldDefnH  hDefn  ) 

Destroy a field definition.

Parameters:
hDefn handle to the field definition to destroy.
OGRJustification OGR_Fld_GetJustify ( OGRFieldDefnH  hDefn  ) 

Get the justification for this field.

This function is the same as the CPP method OGRFieldDefn::GetJustify().

Parameters:
hDefn handle to the field definition to get justification from.
Returns:
the justification.
const char* OGR_Fld_GetNameRef ( OGRFieldDefnH  hDefn  ) 

Fetch name of this field.

This function is the same as the CPP method OGRFieldDefn::GetNameRef().

Parameters:
hDefn handle to the field definition.
Returns:
the name of the field definition.
int OGR_Fld_GetPrecision ( OGRFieldDefnH  hDefn  ) 

Get the formatting precision for this field.

This should normally be zero for fields of types other than OFTReal.

This function is the same as the CPP method OGRFieldDefn::GetPrecision().

Parameters:
hDefn handle to the field definition to get precision from.
Returns:
the precision.
OGRFieldSubType OGR_Fld_GetSubType ( OGRFieldDefnH  hDefn  ) 

Fetch subtype of this field.

This function is the same as the CPP method OGRFieldDefn::GetSubType().

Parameters:
hDefn handle to the field definition to get subtype from.
Returns:
field subtype.
Since:
GDAL 2.0
OGRFieldType OGR_Fld_GetType ( OGRFieldDefnH  hDefn  ) 

Fetch type of this field.

This function is the same as the CPP method OGRFieldDefn::GetType().

Parameters:
hDefn handle to the field definition to get type from.
Returns:
field type.
int OGR_Fld_GetWidth ( OGRFieldDefnH  hDefn  ) 

Get the formatting width for this field.

This function is the same as the CPP method OGRFieldDefn::GetWidth().

Parameters:
hDefn handle to the field definition to get width from.
Returns:
the width, zero means no specified width.
int OGR_Fld_IsIgnored ( OGRFieldDefnH  hDefn  ) 

Return whether this field should be omitted when fetching features.

This method is the same as the C++ method OGRFieldDefn::IsIgnored().

Parameters:
hDefn handle to the field definition
Returns:
ignore state
void OGR_Fld_Set ( OGRFieldDefnH  hDefn,
const char *  pszNameIn,
OGRFieldType  eTypeIn,
int  nWidthIn,
int  nPrecisionIn,
OGRJustification  eJustifyIn 
)

Set defining parameters for a field in one call.

This function is the same as the CPP method OGRFieldDefn::Set().

Parameters:
hDefn handle to the field definition to set to.
pszNameIn the new name to assign.
eTypeIn the new type (one of the OFT values like OFTInteger).
nWidthIn the preferred formatting width. Defaults to zero indicating undefined.
nPrecisionIn number of decimals places for formatting, defaults to zero indicating undefined.
eJustifyIn the formatting justification (OJLeft or OJRight), defaults to OJUndefined.
void OGR_Fld_SetIgnored ( OGRFieldDefnH  hDefn,
int  ignore 
)

Set whether this field should be omitted when fetching features.

This method is the same as the C++ method OGRFieldDefn::SetIgnored().

Parameters:
hDefn handle to the field definition
ignore ignore state
void OGR_Fld_SetJustify ( OGRFieldDefnH  hDefn,
OGRJustification  eJustify 
)

Set the justification for this field.

This function is the same as the CPP method OGRFieldDefn::SetJustify().

Parameters:
hDefn handle to the field definition to set justification to.
eJustify the new justification.
void OGR_Fld_SetName ( OGRFieldDefnH  hDefn,
const char *  pszName 
)

Reset the name of this field.

This function is the same as the CPP method OGRFieldDefn::SetName().

Parameters:
hDefn handle to the field definition to apply the new name to.
pszName the new name to apply.
void OGR_Fld_SetPrecision ( OGRFieldDefnH  hDefn,
int  nPrecision 
)

Set the formatting precision for this field in characters.

This should normally be zero for fields of types other than OFTReal.

This function is the same as the CPP method OGRFieldDefn::SetPrecision().

Parameters:
hDefn handle to the field definition to set precision to.
nPrecision the new precision.
void OGR_Fld_SetSubType ( OGRFieldDefnH  hDefn,
OGRFieldSubType  eSubType 
)

Set the subtype of this field.

This should never be done to an OGRFieldDefn that is already part of an OGRFeatureDefn.

This function is the same as the CPP method OGRFieldDefn::SetSubType().

Parameters:
hDefn handle to the field definition to set type to.
eSubType the new field subtype.
Since:
GDAL 2.0
void OGR_Fld_SetType ( OGRFieldDefnH  hDefn,
OGRFieldType  eType 
)

Set the type of this field.

This should never be done to an OGRFieldDefn that is already part of an OGRFeatureDefn.

This function is the same as the CPP method OGRFieldDefn::SetType().

Parameters:
hDefn handle to the field definition to set type to.
eType the new field type.
void OGR_Fld_SetWidth ( OGRFieldDefnH  hDefn,
int  nNewWidth 
)

Set the formatting width for this field in characters.

This function is the same as the CPP method OGRFieldDefn::SetWidth().

Parameters:
hDefn handle to the field definition to set width to.
nNewWidth the new width.
OGRErr OGR_G_AddGeometry ( OGRGeometryH  hGeom,
OGRGeometryH  hNewSubGeom 
)

Add a geometry to a geometry container.

Some subclasses of OGRGeometryCollection restrict the types of geometry that can be added, and may return an error. The passed geometry is cloned to make an internal copy.

There is no SFCOM analog to this method.

This function is the same as the CPP method OGRGeometryCollection::addGeometry.

For a polygon, hNewSubGeom must be a linearring. If the polygon is empty, the first added subgeometry will be the exterior ring. The next ones will be the interior rings.

Parameters:
hGeom existing geometry container.
hNewSubGeom geometry to add to the container.
Returns:
OGRERR_NONE if successful, or OGRERR_UNSUPPORTED_GEOMETRY_TYPE if the geometry type is illegal for the type of existing geometry.
OGRErr OGR_G_AddGeometryDirectly ( OGRGeometryH  hGeom,
OGRGeometryH  hNewSubGeom 
)

Add a geometry directly to an existing geometry container.

Some subclasses of OGRGeometryCollection restrict the types of geometry that can be added, and may return an error. Ownership of the passed geometry is taken by the container rather than cloning as addGeometry() does.

This function is the same as the CPP method OGRGeometryCollection::addGeometryDirectly.

There is no SFCOM analog to this method.

For a polygon, hNewSubGeom must be a linearring. If the polygon is empty, the first added subgeometry will be the exterior ring. The next ones will be the interior rings.

Parameters:
hGeom existing geometry.
hNewSubGeom geometry to add to the existing geometry.
Returns:
OGRERR_NONE if successful, or OGRERR_UNSUPPORTED_GEOMETRY_TYPE if the geometry type is illegal for the type of geometry container.
void OGR_G_AddPoint ( OGRGeometryH  hGeom,
double  dfX,
double  dfY,
double  dfZ 
)

Add a point to a geometry (line string or point).

The vertex count of the line string is increased by one, and assigned from the passed location value.

Parameters:
hGeom handle to the geometry to add a point to.
dfX x coordinate of point to add.
dfY y coordinate of point to add.
dfZ z coordinate of point to add.
void OGR_G_AddPoint_2D ( OGRGeometryH  hGeom,
double  dfX,
double  dfY 
)

Add a point to a geometry (line string or point).

The vertex count of the line string is increased by one, and assigned from the passed location value.

Parameters:
hGeom handle to the geometry to add a point to.
dfX x coordinate of point to add.
dfY y coordinate of point to add.
OGRGeometryH OGR_G_ApproximateArcAngles ( double  dfCenterX,
double  dfCenterY,
double  dfZ,
double  dfPrimaryRadius,
double  dfSecondaryRadius,
double  dfRotation,
double  dfStartAngle,
double  dfEndAngle,
double  dfMaxAngleStepSizeDegrees 
)

Stroke arc to linestring.

Stroke an arc of a circle to a linestring based on a center point, radius, start angle and end angle, all angles in degrees.

If the dfMaxAngleStepSizeDegrees is zero, then a default value will be used. This is currently 4 degrees unless the user has overridden the value with the OGR_ARC_STEPSIZE configuration variable.

See also:
CPLSetConfigOption()
Parameters:
dfCenterX center X
dfCenterY center Y
dfZ center Z
dfPrimaryRadius X radius of ellipse.
dfSecondaryRadius Y radius of ellipse.
dfRotation rotation of the ellipse clockwise.
dfStartAngle angle to first point on arc (clockwise of X-positive)
dfEndAngle angle to last point on arc (clockwise of X-positive)
dfMaxAngleStepSizeDegrees the largest step in degrees along the arc, zero to use the default setting.
Returns:
OGRLineString geometry representing an approximation of the arc.
Since:
OGR 1.8.0
double OGR_G_Area ( OGRGeometryH  hGeom  ) 

Compute geometry area.

Computes the area for an OGRLinearRing, OGRPolygon or OGRMultiPolygon. Undefined for all other geometry types (returns zero).

This function utilizes the C++ get_Area() methods such as OGRPolygon::get_Area().

Parameters:
hGeom the geometry to operate on.
Returns:
the area or 0.0 for unsupported geometry types.
Since:
OGR 1.8.0
void OGR_G_AssignSpatialReference ( OGRGeometryH  hGeom,
OGRSpatialReferenceH  hSRS 
)

Assign spatial reference to this object.

Any existing spatial reference is replaced, but under no circumstances does this result in the object being reprojected. It is just changing the interpretation of the existing geometry. Note that assigning a spatial reference increments the reference count on the OGRSpatialReference, but does not copy it.

This is similar to the SFCOM IGeometry::put_SpatialReference() method.

This function is the same as the CPP method OGRGeometry::assignSpatialReference.

Parameters:
hGeom handle on the geometry to apply the new spatial reference system.
hSRS handle on the new spatial reference system to apply.
OGRGeometryH OGR_G_Boundary ( OGRGeometryH  hTarget  ) 

Compute boundary.

A new geometry object is created and returned containing the boundary of the geometry on which the method is invoked.

This function is the same as the C++ method OGR_G_Boundary().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Parameters:
hTarget The Geometry to calculate the boundary of.
Returns:
a handle to a newly allocated geometry now owned by the caller, or NULL on failure.
Since:
OGR 1.8.0
OGRGeometryH OGR_G_Buffer ( OGRGeometryH  hTarget,
double  dfDist,
int  nQuadSegs 
)

Compute buffer of geometry.

Builds a new geometry containing the buffer region around the geometry on which it is invoked. The buffer is a polygon containing the region within the buffer distance of the original geometry.

Some buffer sections are properly described as curves, but are converted to approximate polygons. The nQuadSegs parameter can be used to control how many segements should be used to define a 90 degree curve - a quadrant of a circle. A value of 30 is a reasonable default. Large values result in large numbers of vertices in the resulting buffer geometry while small numbers reduce the accuracy of the result.

This function is the same as the C++ method OGRGeometry::Buffer().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Parameters:
hTarget the geometry.
dfDist the buffer distance to be applied. Should be expressed into the same unit as the coordinates of the geometry.
nQuadSegs the number of segments used to approximate a 90 degree (quadrant) of curvature.
Returns:
the newly created geometry, or NULL if an error occurs.
int OGR_G_Centroid ( OGRGeometryH  hGeom,
OGRGeometryH  hCentroidPoint 
)

Compute the geometry centroid.

The centroid location is applied to the passed in OGRPoint object. The centroid is not necessarily within the geometry.

This method relates to the SFCOM ISurface::get_Centroid() method however the current implementation based on GEOS can operate on other geometry types such as multipoint, linestring, geometrycollection such as multipolygons. OGC SF SQL 1.1 defines the operation for surfaces (polygons). SQL/MM-Part 3 defines the operation for surfaces and multisurfaces (multipolygons).

This function is the same as the C++ method OGRGeometry::Centroid().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Returns:
OGRERR_NONE on success or OGRERR_FAILURE on error.
OGRGeometryH OGR_G_Clone ( OGRGeometryH  hGeom  ) 

Make a copy of this object.

This function relates to the SFCOM IGeometry::clone() method.

This function is the same as the CPP method OGRGeometry::clone().

Parameters:
hGeom handle on the geometry to clone from.
Returns:
an handle on the copy of the geometry with the spatial reference system as the original.
void OGR_G_CloseRings ( OGRGeometryH  hGeom  ) 

Force rings to be closed.

If this geometry, or any contained geometries has polygon rings that are not closed, they will be closed by adding the starting point at the end.

Parameters:
hGeom handle to the geometry.
int OGR_G_Contains ( OGRGeometryH  hThis,
OGRGeometryH  hOther 
)

Test for containment.

Tests if this geometry contains the other geometry.

This function is the same as the C++ method OGRGeometry::Contains().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Parameters:
hThis the geometry to compare.
hOther the other geometry to compare.
Returns:
TRUE if hThis contains hOther geometry, otherwise FALSE.
OGRGeometryH OGR_G_ConvexHull ( OGRGeometryH  hTarget  ) 

Compute convex hull.

A new geometry object is created and returned containing the convex hull of the geometry on which the method is invoked.

This function is the same as the C++ method OGRGeometry::ConvexHull().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Parameters:
hTarget The Geometry to calculate the convex hull of.
Returns:
a handle to a newly allocated geometry now owned by the caller, or NULL on failure.
OGRGeometryH OGR_G_CreateFromGML ( const char *  pszGML  ) 

Create geometry from GML.

This method translates a fragment of GML containing only the geometry portion into a corresponding OGRGeometry. There are many limitations on the forms of GML geometries supported by this parser, but they are too numerous to list here.

The following GML2 elements are parsed : Point, LineString, Polygon, MultiPoint, MultiLineString, MultiPolygon, MultiGeometry.

(OGR >= 1.8.0) The following GML3 elements are parsed : Surface, MultiSurface, PolygonPatch, Triangle, Rectangle, Curve, MultiCurve, CompositeCurve, LineStringSegment, Arc, Circle, CompositeSurface, OrientableSurface, Solid, Tin, TriangulatedSurface.

Arc and Circle elements are stroked to linestring, by using a 4 degrees step, unless the user has overridden the value with the OGR_ARC_STEPSIZE configuration variable.

The C++ method OGRGeometryFactory::createFromGML() is the same as this function.

Parameters:
pszGML The GML fragment for the geometry.
Returns:
a geometry on succes, or NULL on error.
OGRErr OGR_G_CreateFromWkb ( unsigned char *  pabyData,
OGRSpatialReferenceH  hSRS,
OGRGeometryH *  phGeometry,
int  nBytes 
)

Create a geometry object of the appropriate type from it's well known binary representation.

Note that if nBytes is passed as zero, no checking can be done on whether the pabyData is sufficient. This can result in a crash if the input data is corrupt. This function returns no indication of the number of bytes from the data source actually used to represent the returned geometry object. Use OGR_G_WkbSize() on the returned geometry to establish the number of bytes it required in WKB format.

The OGRGeometryFactory::createFromWkb() CPP method is the same as this function.

Parameters:
pabyData pointer to the input BLOB data.
hSRS handle to the spatial reference to be assigned to the created geometry object. This may be NULL.
phGeometry the newly created geometry object will be assigned to the indicated handle on return. This will be NULL in case of failure. If not NULL, *phGeometry should be freed with OGR_G_DestroyGeometry() after use.
nBytes the number of bytes of data available in pabyData, or -1 if it is not known, but assumed to be sufficient.
Returns:
OGRERR_NONE if all goes well, otherwise any of OGRERR_NOT_ENOUGH_DATA, OGRERR_UNSUPPORTED_GEOMETRY_TYPE, or OGRERR_CORRUPT_DATA may be returned.
OGRErr OGR_G_CreateFromWkt ( char **  ppszData,
OGRSpatialReferenceH  hSRS,
OGRGeometryH *  phGeometry 
)

Create a geometry object of the appropriate type from it's well known text representation.

The OGRGeometryFactory::createFromWkt CPP method is the same as this function.

Parameters:
ppszData input zero terminated string containing well known text representation of the geometry to be created. The pointer is updated to point just beyond that last character consumed.
hSRS handle to the spatial reference to be assigned to the created geometry object. This may be NULL.
phGeometry the newly created geometry object will be assigned to the indicated handle on return. This will be NULL if the method fails. If not NULL, *phGeometry should be freed with OGR_G_DestroyGeometry() after use.
Returns:
OGRERR_NONE if all goes well, otherwise any of OGRERR_NOT_ENOUGH_DATA, OGRERR_UNSUPPORTED_GEOMETRY_TYPE, or OGRERR_CORRUPT_DATA may be returned.
OGRGeometryH OGR_G_CreateGeometry ( OGRwkbGeometryType  eGeometryType  ) 

Create an empty geometry of desired type.

This is equivalent to allocating the desired geometry with new, but the allocation is guaranteed to take place in the context of the GDAL/OGR heap.

This function is the same as the CPP method OGRGeometryFactory::createGeometry.

Parameters:
eGeometryType the type code of the geometry to be created.
Returns:
handle to the newly create geometry or NULL on failure. Should be freed with OGR_G_DestroyGeometry() after use.
int OGR_G_Crosses ( OGRGeometryH  hThis,
OGRGeometryH  hOther 
)

Test for crossing.

Tests if this geometry and the other geometry are crossing.

This function is the same as the C++ method OGRGeometry::Crosses().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Parameters:
hThis the geometry to compare.
hOther the other geometry to compare.
Returns:
TRUE if they are crossing, otherwise FALSE.
void OGR_G_DestroyGeometry ( OGRGeometryH  hGeom  ) 

Destroy geometry object.

Equivalent to invoking delete on a geometry, but it guaranteed to take place within the context of the GDAL/OGR heap.

This function is the same as the CPP method OGRGeometryFactory::destroyGeometry.

Parameters:
hGeom handle to the geometry to delete.
OGRGeometryH OGR_G_Difference ( OGRGeometryH  hThis,
OGRGeometryH  hOther 
)

Compute difference.

Generates a new geometry which is the region of this geometry with the region of the other geometry removed.

This function is the same as the C++ method OGRGeometry::Difference().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Parameters:
hThis the geometry.
hOther the other geometry.
Returns:
a new geometry representing the difference or NULL if the difference is empty or an error occurs.
int OGR_G_Disjoint ( OGRGeometryH  hThis,
OGRGeometryH  hOther 
)

Test for disjointness.

Tests if this geometry and the other geometry are disjoint.

This function is the same as the C++ method OGRGeometry::Disjoint().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Parameters:
hThis the geometry to compare.
hOther the other geometry to compare.
Returns:
TRUE if they are disjoint, otherwise FALSE.
double OGR_G_Distance ( OGRGeometryH  hFirst,
OGRGeometryH  hOther 
)

Compute distance between two geometries.

Returns the shortest distance between the two geometries. The distance is expressed into the same unit as the coordinates of the geometries.

This function is the same as the C++ method OGRGeometry::Distance().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Parameters:
hFirst the first geometry to compare against.
hOther the other geometry to compare against.
Returns:
the distance between the geometries or -1 if an error occurs.
void OGR_G_DumpReadable ( OGRGeometryH  hGeom,
FILE *  fp,
const char *  pszPrefix 
)

Dump geometry in well known text format to indicated output file.

This method is the same as the CPP method OGRGeometry::dumpReadable.

Parameters:
hGeom handle on the geometry to dump.
fp the text file to write the geometry to.
pszPrefix the prefix to put on each line of output.
void OGR_G_Empty ( OGRGeometryH  hGeom  ) 

Clear geometry information.

This restores the geometry to it's initial state after construction, and before assignment of actual geometry.

This function relates to the SFCOM IGeometry::Empty() method.

This function is the same as the CPP method OGRGeometry::empty().

Parameters:
hGeom handle on the geometry to empty.
int OGR_G_Equals ( OGRGeometryH  hGeom,
OGRGeometryH  hOther 
)

Returns TRUE if two geometries are equivalent.

This function is the same as the CPP method OGRGeometry::Equals() method.

Parameters:
hGeom handle on the first geometry.
hOther handle on the other geometry to test against.
Returns:
TRUE if equivalent or FALSE otherwise.
char* OGR_G_ExportToGML ( OGRGeometryH  hGeometry  ) 

Convert a geometry into GML format.

The GML geometry is expressed directly in terms of GML basic data types assuming the this is available in the gml namespace. The returned string should be freed with CPLFree() when no longer required.

This method is the same as the C++ method OGRGeometry::exportToGML().

Parameters:
hGeometry handle to the geometry.
Returns:
A GML fragment or NULL in case of error.
char* OGR_G_ExportToGMLEx ( OGRGeometryH  hGeometry,
char **  papszOptions 
)

Convert a geometry into GML format.

The GML geometry is expressed directly in terms of GML basic data types assuming the this is available in the gml namespace. The returned string should be freed with CPLFree() when no longer required.

The supported options are :

  • FORMAT=GML3. Otherwise it will default to GML 2.1.2 output.
  • GML3_LINESTRING_ELEMENT=curve. (Only valid for FORMAT=GML3) To use gml:Curve element for linestrings. Otherwise gml:LineString will be used .
  • GML3_LONGSRS=YES/NO. (Only valid for FORMAT=GML3) Default to YES. If YES, SRS with EPSG authority will be written with the "urn:ogc:def:crs:EPSG::" prefix. In the case, if the SRS is a geographic SRS without explicit AXIS order, but that the same SRS authority code imported with ImportFromEPSGA() should be treated as lat/long, then the function will take care of coordinate order swapping. If set to NO, SRS with EPSG authority will be written with the "EPSG:" prefix, even if they are in lat/long order.
  • GMLID=astring. If specified, a gml:id attribute will be written in the top-level geometry element with the provided value. Required for GML 3.2 compatibility.
  • SRSDIMENSION_LOC=POSLIST/GEOMETRY/GEOMETRY,POSLIST. (Only valid for FORMAT=GML3, GDAL >= 2.0) Default to POSLIST. For 2.5D geometries, define the location where to attach the srsDimension attribute. There are diverging implementations. Some put in on the <gml:posList> element, other on the top geometry element.

Note that curve geometries like CIRCULARSTRING, COMPOUNDCURVE, CURVEPOLYGON, MULTICURVE or MULTISURFACE are not supported in GML 2.

This method is the same as the C++ method OGRGeometry::exportToGML().

Parameters:
hGeometry handle to the geometry.
papszOptions NULL-terminated list of options.
Returns:
A GML fragment or NULL in case of error.
Since:
OGR 1.8.0
OGRErr OGR_G_ExportToIsoWkb ( OGRGeometryH  hGeom,
OGRwkbByteOrder  eOrder,
unsigned char *  pabyDstBuffer 
)

Convert a geometry into SFSQL 1.2 / ISO SQL/MM Part 3 well known binary format.

This function relates to the SFCOM IWks::ExportToWKB() method. It exports the SFSQL 1.2 and ISO SQL/MM Part 3 extended dimension (Z&M) WKB types

This function is the same as the CPP method OGRGeometry::exportToWkb(OGRwkbByteOrder, unsigned char *, OGRwkbVariant) with eWkbVariant = wkbVariantIso.

Parameters:
hGeom handle on the geometry to convert to a well know binary data from.
eOrder One of wkbXDR or wkbNDR indicating MSB or LSB byte order respectively.
pabyDstBuffer a buffer into which the binary representation is written. This buffer must be at least OGR_G_WkbSize() byte in size.
Returns:
Currently OGRERR_NONE is always returned.
Since:
GDAL 2.0
OGRErr OGR_G_ExportToIsoWkt ( OGRGeometryH  hGeom,
char **  ppszSrcText 
)

Convert a geometry into SFSQL 1.2 / ISO SQL/MM Part 3 well known text format.

This function relates to the SFCOM IWks::ExportToWKT() method. It exports the SFSQL 1.2 and ISO SQL/MM Part 3 extended dimension (Z&M) WKB types

This function is the same as the CPP method OGRGeometry::exportToWkt(,wkbVariantIso).

Parameters:
hGeom handle on the geometry to convert to a text format from.
ppszSrcText a text buffer is allocated by the program, and assigned to the passed pointer. After use, *ppszDstText should be freed with OGRFree().
Returns:
Currently OGRERR_NONE is always returned.
Since:
GDAL 2.0
char* OGR_G_ExportToJson ( OGRGeometryH  hGeometry  ) 

Convert a geometry into GeoJSON format.

The returned string should be freed with CPLFree() when no longer required.

This method is the same as the C++ method OGRGeometry::exportToJson().

Parameters:
hGeometry handle to the geometry.
Returns:
A GeoJSON fragment or NULL in case of error.
char* OGR_G_ExportToJsonEx ( OGRGeometryH  hGeometry,
char **  papszOptions 
)

Convert a geometry into GeoJSON format.

The returned string should be freed with CPLFree() when no longer required.

This method is the same as the C++ method OGRGeometry::exportToJson().

Parameters:
hGeometry handle to the geometry.
papszOptions a null terminated list of options. For now, only COORDINATE_PRECISION=int_number where int_number is the maximum number of figures after decimal separator to write in coordinates.
Returns:
A GeoJSON fragment or NULL in case of error.
Since:
OGR 1.9.0
char* OGR_G_ExportToKML ( OGRGeometryH  hGeometry,
const char *  pszAltitudeMode 
)

Convert a geometry into KML format.

The returned string should be freed with CPLFree() when no longer required.

This method is the same as the C++ method OGRGeometry::exportToKML().

Parameters:
hGeometry handle to the geometry.
pszAltitudeMode value to write in altitudeMode element, or NULL.
Returns:
A KML fragment or NULL in case of error.
OGRErr OGR_G_ExportToWkb ( OGRGeometryH  hGeom,
OGRwkbByteOrder  eOrder,
unsigned char *  pabyDstBuffer 
)

Convert a geometry well known binary format.

This function relates to the SFCOM IWks::ExportToWKB() method.

For backward compatibility purposes, it exports the Old-style 99-402 extended dimension (Z) WKB types for types Point, LineString, Polygon, MultiPoint, MultiLineString, MultiPolygon and GeometryCollection. For other geometry types, it is equivalent to OGR_G_ExportToIsoWkb().

This function is the same as the CPP method OGRGeometry::exportToWkb(OGRwkbByteOrder, unsigned char *, OGRwkbVariant) with eWkbVariant = wkbVariantOldOgc.

Parameters:
hGeom handle on the geometry to convert to a well know binary data from.
eOrder One of wkbXDR or wkbNDR indicating MSB or LSB byte order respectively.
pabyDstBuffer a buffer into which the binary representation is written. This buffer must be at least OGR_G_WkbSize() byte in size.
Returns:
Currently OGRERR_NONE is always returned.
OGRErr OGR_G_ExportToWkt ( OGRGeometryH  hGeom,
char **  ppszSrcText 
)

Convert a geometry into well known text format.

This function relates to the SFCOM IWks::ExportToWKT() method.

For backward compatibility purposes, it exports the Old-style 99-402 extended dimension (Z) WKB types for types Point, LineString, Polygon, MultiPoint, MultiLineString, MultiPolygon and GeometryCollection. For other geometry types, it is equivalent to OGR_G_ExportToIsoWkt().

This function is the same as the CPP method OGRGeometry::exportToWkt().

Parameters:
hGeom handle on the geometry to convert to a text format from.
ppszSrcText a text buffer is allocated by the program, and assigned to the passed pointer. After use, *ppszDstText should be freed with OGRFree().
Returns:
Currently OGRERR_NONE is always returned.
void OGR_G_FlattenTo2D ( OGRGeometryH  hGeom  ) 

Convert geometry to strictly 2D.

In a sense this converts all Z coordinates to 0.0.

This function is the same as the CPP method OGRGeometry::flattenTo2D().

Parameters:
hGeom handle on the geometry to convert.
OGRGeometryH OGR_G_ForceTo ( OGRGeometryH  hGeom,
OGRwkbGeometryType  eTargetType,
char **  papszOptions 
)

Convert to another geometry type.

This function is the same as the C++ method OGRGeometryFactory::forceTo().

Parameters:
hGeom the input geometry - ownership is passed to the method.
eTargetType target output geometry type.
papszOptions options as a null-terminated list of strings or NULL.
Returns:
new geometry.
Since:
GDAL 2.0
OGRGeometryH OGR_G_ForceToLineString ( OGRGeometryH  hGeom  ) 

Convert to line string.

This function is the same as the C++ method OGRGeometryFactory::forceToLineString().

Parameters:
hGeom handle to the geometry to convert (ownership surrendered).
Returns:
the converted geometry (ownership to caller).
Since:
GDAL/OGR 1.10.0
OGRGeometryH OGR_G_ForceToMultiLineString ( OGRGeometryH  hGeom  ) 

Convert to multilinestring.

This function is the same as the C++ method OGRGeometryFactory::forceToMultiLineString().

Parameters:
hGeom handle to the geometry to convert (ownership surrendered).
Returns:
the converted geometry (ownership to caller).
Since:
GDAL/OGR 1.8.0
OGRGeometryH OGR_G_ForceToMultiPoint ( OGRGeometryH  hGeom  ) 

Convert to multipoint.

This function is the same as the C++ method OGRGeometryFactory::forceToMultiPoint().

Parameters:
hGeom handle to the geometry to convert (ownership surrendered).
Returns:
the converted geometry (ownership to caller).
Since:
GDAL/OGR 1.8.0
OGRGeometryH OGR_G_ForceToMultiPolygon ( OGRGeometryH  hGeom  ) 

Convert to multipolygon.

This function is the same as the C++ method OGRGeometryFactory::forceToMultiPolygon().

Parameters:
hGeom handle to the geometry to convert (ownership surrendered).
Returns:
the converted geometry (ownership to caller).
Since:
GDAL/OGR 1.8.0
OGRGeometryH OGR_G_ForceToPolygon ( OGRGeometryH  hGeom  ) 

Convert to polygon.

This function is the same as the C++ method OGRGeometryFactory::forceToPolygon().

Parameters:
hGeom handle to the geometry to convert (ownership surrendered).
Returns:
the converted geometry (ownership to caller).
Since:
GDAL/OGR 1.8.0
double OGR_G_GetArea ( OGRGeometryH  hGeom  ) 

Compute geometry area (deprecated).

Deprecated:
See also:
OGR_G_Area()
OGRGeometryH OGR_G_GetBoundary ( OGRGeometryH  hTarget  ) 

Compute boundary (deprecated).

Deprecated:
See also:
OGR_G_Boundary()
int OGR_G_GetCoordinateDimension ( OGRGeometryH  hGeom  ) 

Get the dimension of the coordinates in this geometry.

This function corresponds to the SFCOM IGeometry::GetDimension() method.

This function is the same as the CPP method OGRGeometry::getCoordinateDimension().

Parameters:
hGeom handle on the geometry to get the dimension of the coordinates from.
Returns:
in practice this will return 2 or 3. It can also return 0 in the case of an empty point.
OGRGeometryH OGR_G_GetCurveGeometry ( OGRGeometryH  hGeom,
char **  papszOptions 
)

Return curve version of this geometry.

Returns a geometry that has possibly CIRCULARSTRING, COMPOUNDCURVE, CURVEPOLYGON, MULTICURVE or MULTISURFACE in it, by de-approximating linear into curve geometries.

If the geometry has no curve portion, the returned geometry will be a clone of it.

The ownership of the returned geometry belongs to the caller.

The reverse function is OGR_G_GetLinearGeometry().

This function is the same as C++ method OGRGeometry::getCurveGeometry().

Parameters:
hGeom the geometry to operate on.
papszOptions options as a null-terminated list of strings. Unused for now. Must be set to NULL.
Returns:
a new geometry.
Since:
GDAL 2.0
int OGR_G_GetDimension ( OGRGeometryH  hGeom  ) 

Get the dimension of this geometry.

This function corresponds to the SFCOM IGeometry::GetDimension() method. It indicates the dimension of the geometry, but does not indicate the dimension of the underlying space (as indicated by OGR_G_GetCoordinateDimension() function).

This function is the same as the CPP method OGRGeometry::getDimension().

Parameters:
hGeom handle on the geometry to get the dimension from.
Returns:
0 for points, 1 for lines and 2 for surfaces.
void OGR_G_GetEnvelope ( OGRGeometryH  hGeom,
OGREnvelope psEnvelope 
)

Computes and returns the bounding envelope for this geometry in the passed psEnvelope structure.

This function is the same as the CPP method OGRGeometry::getEnvelope().

Parameters:
hGeom handle of the geometry to get envelope from.
psEnvelope the structure in which to place the results.
void OGR_G_GetEnvelope3D ( OGRGeometryH  hGeom,
OGREnvelope3D psEnvelope 
)

Computes and returns the bounding envelope (3D) for this geometry in the passed psEnvelope structure.

This function is the same as the CPP method OGRGeometry::getEnvelope().

Parameters:
hGeom handle of the geometry to get envelope from.
psEnvelope the structure in which to place the results.
Since:
OGR 1.9.0
int OGR_G_GetGeometryCount ( OGRGeometryH  hGeom  ) 

Fetch the number of elements in a geometry or number of geometries in container.

Only geometries of type wkbPolygon[25D], wkbMultiPoint[25D], wkbMultiLineString[25D], wkbMultiPolygon[25D] or wkbGeometryCollection[25D] may return a valid value. Other geometry types will silently return 0.

For a polygon, the returned number is the number of rings (exterior ring + interior rings).

Parameters:
hGeom single geometry or geometry container from which to get the number of elements.
Returns:
the number of elements.
const char* OGR_G_GetGeometryName ( OGRGeometryH  hGeom  ) 

Fetch WKT name for geometry type.

There is no SFCOM analog to this function.

This function is the same as the CPP method OGRGeometry::getGeometryName().

Parameters:
hGeom handle on the geometry to get name from.
Returns:
name used for this geometry type in well known text format.
OGRGeometryH OGR_G_GetGeometryRef ( OGRGeometryH  hGeom,
int  iSubGeom 
)

Fetch geometry from a geometry container.

This function returns an handle to a geometry within the container. The returned geometry remains owned by the container, and should not be modified. The handle is only valid untill the next change to the geometry container. Use OGR_G_Clone() to make a copy.

This function relates to the SFCOM IGeometryCollection::get_Geometry() method.

This function is the same as the CPP method OGRGeometryCollection::getGeometryRef().

For a polygon, OGR_G_GetGeometryRef(iSubGeom) returns the exterior ring if iSubGeom == 0, and the interior rings for iSubGeom > 0.

Parameters:
hGeom handle to the geometry container from which to get a geometry from.
iSubGeom the index of the geometry to fetch, between 0 and getNumGeometries() - 1.
Returns:
handle to the requested geometry.
OGRwkbGeometryType OGR_G_GetGeometryType ( OGRGeometryH  hGeom  ) 

Fetch geometry type.

Note that the geometry type may include the 2.5D flag. To get a 2D flattened version of the geometry type apply the wkbFlatten() macro to the return result.

This function is the same as the CPP method OGRGeometry::getGeometryType().

Parameters:
hGeom handle on the geometry to get type from.
Returns:
the geometry type code.
OGRGeometryH OGR_G_GetLinearGeometry ( OGRGeometryH  hGeom,
double  dfMaxAngleStepSizeDegrees,
char **  papszOptions 
)

Return, possibly approximate, linear version of this geometry.

Returns a geometry that has no CIRCULARSTRING, COMPOUNDCURVE, CURVEPOLYGON, MULTICURVE or MULTISURFACE in it, by approximating curve geometries.

The ownership of the returned geometry belongs to the caller.

The reverse function is OGR_G_GetCurveGeometry().

This method relates to the ISO SQL/MM Part 3 ICurve::CurveToLine() and CurvePolygon::CurvePolyToPoly() methods.

This function is the same as C++ method OGRGeometry::getLinearGeometry().

Parameters:
hGeom the geometry to operate on.
dfMaxAngleStepSizeDegrees the largest step in degrees along the arc, zero to use the default setting.
papszOptions options as a null-terminated list of strings or NULL. See OGRGeometryFactory::curveToLineString() for valid options.
Returns:
a new geometry.
Since:
GDAL 2.0
void OGR_G_GetPoint ( OGRGeometryH  hGeom,
int  i,
double *  pdfX,
double *  pdfY,
double *  pdfZ 
)

Fetch a point in line string or a point geometry.

Parameters:
hGeom handle to the geometry from which to get the coordinates.
i the vertex to fetch, from 0 to getNumPoints()-1, zero for a point.
pdfX value of x coordinate.
pdfY value of y coordinate.
pdfZ value of z coordinate.
int OGR_G_GetPointCount ( OGRGeometryH  hGeom  ) 

Fetch number of points from a geometry.

Only wkbPoint[25D] or wkbLineString[25D] may return a valid value. Other geometry types will silently return 0.

Parameters:
hGeom handle to the geometry from which to get the number of points.
Returns:
the number of points.
int OGR_G_GetPoints ( OGRGeometryH  hGeom,
void *  pabyX,
int  nXStride,
void *  pabyY,
int  nYStride,
void *  pabyZ,
int  nZStride 
)

Returns all points of line string.

This method copies all points into user arrays. The user provides the stride between 2 consecutives elements of the array.

On some CPU architectures, care must be taken so that the arrays are properly aligned.

Parameters:
hGeom handle to the geometry from which to get the coordinates.
pabyX a buffer of at least (sizeof(double) * nXStride * nPointCount) bytes, may be NULL.
nXStride the number of bytes between 2 elements of pabyX.
pabyY a buffer of at least (sizeof(double) * nYStride * nPointCount) bytes, may be NULL.
nYStride the number of bytes between 2 elements of pabyY.
pabyZ a buffer of at last size (sizeof(double) * nZStride * nPointCount) bytes, may be NULL.
nZStride the number of bytes between 2 elements of pabyZ.
Returns:
the number of points
Since:
OGR 1.9.0
OGRSpatialReferenceH OGR_G_GetSpatialReference ( OGRGeometryH  hGeom  ) 

Returns spatial reference system for geometry.

This function relates to the SFCOM IGeometry::get_SpatialReference() method.

This function is the same as the CPP method OGRGeometry::getSpatialReference().

Parameters:
hGeom handle on the geometry to get spatial reference from.
Returns:
a reference to the spatial reference geometry.
double OGR_G_GetX ( OGRGeometryH  hGeom,
int  i 
)

Fetch the x coordinate of a point from a geometry.

Parameters:
hGeom handle to the geometry from which to get the x coordinate.
i point to get the x coordinate.
Returns:
the X coordinate of this point.
double OGR_G_GetY ( OGRGeometryH  hGeom,
int  i 
)

Fetch the x coordinate of a point from a geometry.

Parameters:
hGeom handle to the geometry from which to get the y coordinate.
i point to get the Y coordinate.
Returns:
the Y coordinate of this point.
double OGR_G_GetZ ( OGRGeometryH  hGeom,
int  i 
)

Fetch the z coordinate of a point from a geometry.

Parameters:
hGeom handle to the geometry from which to get the Z coordinate.
i point to get the Z coordinate.
Returns:
the Z coordinate of this point.
int OGR_G_HasCurveGeometry ( OGRGeometryH  hGeom,
int  bLookForNonLinear 
)

Returns if this geometry is or has curve geometry.

Returns if a geometry is or has CIRCULARSTRING, COMPOUNDCURVE, CURVEPOLYGON, MULTICURVE or MULTISURFACE in it.

If bLookForNonLinear is set to TRUE, it will be actually looked if the geometry or its subgeometries are or contain a non-linear geometry in them. In which case, if the method returns TRUE, it means that OGR_G_GetLinearGeometry() would return an approximate version of the geometry. Otherwise, OGR_G_GetLinearGeometry() would do a conversion, but with just converting container type, like COMPOUNDCURVE -> LINESTRING, MULTICURVE -> MULTILINESTRING or MULTISURFACE -> MULTIPOLYGON, resulting in a "loss-less" conversion.

This function is the same as C++ method OGRGeometry::hasCurveGeometry().

Parameters:
hGeom the geometry to operate on.
bLookForNonLinear set it to TRUE to check if the geometry is or contains a CIRCULARSTRING.
Returns:
TRUE if this geometry is or has curve geometry.
Since:
GDAL 2.0
OGRErr OGR_G_ImportFromWkb ( OGRGeometryH  hGeom,
unsigned char *  pabyData,
int  nSize 
)

Assign geometry from well known binary data.

The object must have already been instantiated as the correct derived type of geometry object to match the binaries type.

This function relates to the SFCOM IWks::ImportFromWKB() method.

This function is the same as the CPP method OGRGeometry::importFromWkb().

Parameters:
hGeom handle on the geometry to assign the well know binary data to.
pabyData the binary input data.
nSize the size of pabyData in bytes, or zero if not known.
Returns:
OGRERR_NONE if all goes well, otherwise any of OGRERR_NOT_ENOUGH_DATA, OGRERR_UNSUPPORTED_GEOMETRY_TYPE, or OGRERR_CORRUPT_DATA may be returned.
OGRErr OGR_G_ImportFromWkt ( OGRGeometryH  hGeom,
char **  ppszSrcText 
)

Assign geometry from well known text data.

The object must have already been instantiated as the correct derived type of geometry object to match the text type.

This function relates to the SFCOM IWks::ImportFromWKT() method.

This function is the same as the CPP method OGRGeometry::importFromWkt().

Parameters:
hGeom handle on the geometry to assign well know text data to.
ppszSrcText pointer to a pointer to the source text. The pointer is updated to pointer after the consumed text.
Returns:
OGRERR_NONE if all goes well, otherwise any of OGRERR_NOT_ENOUGH_DATA, OGRERR_UNSUPPORTED_GEOMETRY_TYPE, or OGRERR_CORRUPT_DATA may be returned.
OGRGeometryH OGR_G_Intersection ( OGRGeometryH  hThis,
OGRGeometryH  hOther 
)

Compute intersection.

Generates a new geometry which is the region of intersection of the two geometries operated on. The OGR_G_Intersects() function can be used to test if two geometries intersect.

This function is the same as the C++ method OGRGeometry::Intersection().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Parameters:
hThis the geometry.
hOther the other geometry.
Returns:
a new geometry representing the intersection or NULL if there is no intersection or an error occurs.
int OGR_G_Intersects ( OGRGeometryH  hGeom,
OGRGeometryH  hOtherGeom 
)

Do these features intersect?

Currently this is not implemented in a rigerous fashion, and generally just tests whether the envelopes of the two features intersect. Eventually this will be made rigerous.

This function is the same as the CPP method OGRGeometry::Intersects.

Parameters:
hGeom handle on the first geometry.
hOtherGeom handle on the other geometry to test against.
Returns:
TRUE if the geometries intersect, otherwise FALSE.
int OGR_G_IsEmpty ( OGRGeometryH  hGeom  ) 

Test if the geometry is empty.

This method is the same as the CPP method OGRGeometry::IsEmpty().

Parameters:
hGeom The Geometry to test.
Returns:
TRUE if the geometry has no points, otherwise FALSE.
int OGR_G_IsRing ( OGRGeometryH  hGeom  ) 

Test if the geometry is a ring.

This function is the same as the C++ method OGRGeometry::IsRing().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always return FALSE.

Parameters:
hGeom The Geometry to test.
Returns:
TRUE if the geometry has no points, otherwise FALSE.
int OGR_G_IsSimple ( OGRGeometryH  hGeom  ) 

Returns TRUE if the geometry is simple.

Returns TRUE if the geometry has no anomalous geometric points, such as self intersection or self tangency. The description of each instantiable geometric class will include the specific conditions that cause an instance of that class to be classified as not simple.

This function is the same as the c++ method OGRGeometry::IsSimple() method.

If OGR is built without the GEOS library, this function will always return FALSE.

Parameters:
hGeom The Geometry to test.
Returns:
TRUE if object is simple, otherwise FALSE.
int OGR_G_IsValid ( OGRGeometryH  hGeom  ) 

Test if the geometry is valid.

This function is the same as the C++ method OGRGeometry::IsValid().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always return FALSE.

Parameters:
hGeom The Geometry to test.
Returns:
TRUE if the geometry has no points, otherwise FALSE.
double OGR_G_Length ( OGRGeometryH  hGeom  ) 

Compute length of a geometry.

Computes the length for OGRCurve or MultiCurve objects. Undefined for all other geometry types (returns zero).

This function utilizes the C++ get_Length() method.

Parameters:
hGeom the geometry to operate on.
Returns:
the lenght or 0.0 for unsupported geometry types.
Since:
OGR 1.8.0
int OGR_G_Overlaps ( OGRGeometryH  hThis,
OGRGeometryH  hOther 
)

Test for overlap.

Tests if this geometry and the other geometry overlap, that is their intersection has a non-zero area.

This function is the same as the C++ method OGRGeometry::Overlaps().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Parameters:
hThis the geometry to compare.
hOther the other geometry to compare.
Returns:
TRUE if they are overlapping, otherwise FALSE.
OGRGeometryH OGR_G_PointOnSurface ( OGRGeometryH  hGeom  ) 

Returns a point guaranteed to lie on the surface.

This method relates to the SFCOM ISurface::get_PointOnSurface() method however the current implementation based on GEOS can operate on other geometry types than the types that are supported by SQL/MM-Part 3 : surfaces (polygons) and multisurfaces (multipolygons).

This method is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this method will always fail, issuing a CPLE_NotSupported error.

Parameters:
hGeom the geometry to operate on.
Returns:
a point guaranteed to lie on the surface or NULL if an error occured.
Since:
OGR 1.10
OGRGeometryH OGR_G_Polygonize ( OGRGeometryH  hTarget  ) 

Polygonizes a set of sparse edges.

A new geometry object is created and returned containing a collection of reassembled Polygons: NULL will be returned if the input collection doesn't corresponds to a MultiLinestring, or when reassembling Edges into Polygons is impossible due to topogical inconsistencies.

This function is the same as the C++ method OGRGeometry::Polygonize().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Parameters:
hTarget The Geometry to be polygonized.
Returns:
a handle to a newly allocated geometry now owned by the caller, or NULL on failure.
Since:
OGR 1.9.0
OGRErr OGR_G_RemoveGeometry ( OGRGeometryH  hGeom,
int  iGeom,
int  bDelete 
)

Remove a geometry from an exiting geometry container.

Removing a geometry will cause the geometry count to drop by one, and all "higher" geometries will shuffle down one in index.

There is no SFCOM analog to this method.

This function is the same as the CPP method OGRGeometryCollection::removeGeometry().

Parameters:
hGeom the existing geometry to delete from.
iGeom the index of the geometry to delete. A value of -1 is a special flag meaning that all geometries should be removed.
bDelete if TRUE the geometry will be destroyed, otherwise it will not. The default is TRUE as the existing geometry is considered to own the geometries in it.
Returns:
OGRERR_NONE if successful, or OGRERR_FAILURE if the index is out of range.
void OGR_G_Segmentize ( OGRGeometryH  hGeom,
double  dfMaxLength 
)

Modify the geometry such it has no segment longer then the given distance.

Interpolated points will have Z and M values (if needed) set to 0. Distance computation is performed in 2d only

This function is the same as the CPP method OGRGeometry::segmentize().

Parameters:
hGeom handle on the geometry to segmentize
dfMaxLength the maximum distance between 2 points after segmentization
void OGR_G_SetCoordinateDimension ( OGRGeometryH  hGeom,
int  nNewDimension 
)

Set the coordinate dimension.

This method sets the explicit coordinate dimension. Setting the coordinate dimension of a geometry to 2 should zero out any existing Z values. Setting the dimension of a geometry collection will not necessarily affect the children geometries.

Parameters:
hGeom handle on the geometry to set the dimension of the coordinates.
nNewDimension New coordinate dimension value, either 2 or 3.
void OGR_G_SetPoint ( OGRGeometryH  hGeom,
int  i,
double  dfX,
double  dfY,
double  dfZ 
)

Set the location of a vertex in a point or linestring geometry.

If iPoint is larger than the number of existing points in the linestring, the point count will be increased to accommodate the request.

Parameters:
hGeom handle to the geometry to add a vertex to.
i the index of the vertex to assign (zero based) or zero for a point.
dfX input X coordinate to assign.
dfY input Y coordinate to assign.
dfZ input Z coordinate to assign (defaults to zero).
void OGR_G_SetPoint_2D ( OGRGeometryH  hGeom,
int  i,
double  dfX,
double  dfY 
)

Set the location of a vertex in a point or linestring geometry.

If iPoint is larger than the number of existing points in the linestring, the point count will be increased to accommodate the request.

Parameters:
hGeom handle to the geometry to add a vertex to.
i the index of the vertex to assign (zero based) or zero for a point.
dfX input X coordinate to assign.
dfY input Y coordinate to assign.
void OGR_G_SetPointCount ( OGRGeometryH  hGeom,
int  nNewPointCount 
)

Set number of points in a geometry.

This method primary exists to preset the number of points in a linestring geometry before setPoint() is used to assign them to avoid reallocating the array larger with each call to addPoint().

Parameters:
nNewPointCount the new number of points for geometry.
void OGR_G_SetPoints ( OGRGeometryH  hGeom,
int  nPointsIn,
void *  pabyX,
int  nXStride,
void *  pabyY,
int  nYStride,
void *  pabyZ,
int  nZStride 
)

Assign all points in a point or a line string geometry.

This method clear any existing points assigned to this geometry, and assigns a whole new set.

Parameters:
hGeom handle to the geometry to set the coordinates.
nPointsIn number of points being passed in padfX and padfY.
padfX list of X coordinates of points being assigned.
nXStride the number of bytes between 2 elements of pabyX.
padfY list of Y coordinates of points being assigned.
nYStride the number of bytes between 2 elements of pabyY.
padfZ list of Z coordinates of points being assigned (defaults to NULL for 2D objects).
nZStride the number of bytes between 2 elements of pabyZ.
OGRGeometryH OGR_G_Simplify ( OGRGeometryH  hThis,
double  dTolerance 
)

Compute a simplified geometry.

This function is the same as the C++ method OGRGeometry::Simplify().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Parameters:
hThis the geometry.
dTolerance the distance tolerance for the simplification.
Returns:
the simplified geometry or NULL if an error occurs.
Since:
OGR 1.8.0
OGRGeometryH OGR_G_SimplifyPreserveTopology ( OGRGeometryH  hThis,
double  dTolerance 
)

Simplify the geometry while preserving topology.

This function is the same as the C++ method OGRGeometry::SimplifyPreserveTopology().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Parameters:
hThis the geometry.
dTolerance the distance tolerance for the simplification.
Returns:
the simplified geometry or NULL if an error occurs.
Since:
OGR 1.9.0
OGRGeometryH OGR_G_SymDifference ( OGRGeometryH  hThis,
OGRGeometryH  hOther 
)

Compute symmetric difference.

Generates a new geometry which is the symmetric difference of this geometry and the other geometry.

This function is the same as the C++ method OGRGeometry::SymmetricDifference().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Parameters:
hThis the geometry.
hOther the other geometry.
Returns:
a new geometry representing the symmetric difference or NULL if the difference is empty or an error occurs.
Since:
OGR 1.8.0
OGRGeometryH OGR_G_SymmetricDifference ( OGRGeometryH  hThis,
OGRGeometryH  hOther 
)

Compute symmetric difference (deprecated).

Deprecated:
See also:
OGR_G_SymmetricDifference()
int OGR_G_Touches ( OGRGeometryH  hThis,
OGRGeometryH  hOther 
)

Test for touching.

Tests if this geometry and the other geometry are touching.

This function is the same as the C++ method OGRGeometry::Touches().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Parameters:
hThis the geometry to compare.
hOther the other geometry to compare.
Returns:
TRUE if they are touching, otherwise FALSE.
OGRErr OGR_G_Transform ( OGRGeometryH  hGeom,
OGRCoordinateTransformationH  hTransform 
)

Apply arbitrary coordinate transformation to geometry.

This function will transform the coordinates of a geometry from their current spatial reference system to a new target spatial reference system. Normally this means reprojecting the vectors, but it could include datum shifts, and changes of units.

Note that this function does not require that the geometry already have a spatial reference system. It will be assumed that they can be treated as having the source spatial reference system of the OGRCoordinateTransformation object, and the actual SRS of the geometry will be ignored. On successful completion the output OGRSpatialReference of the OGRCoordinateTransformation will be assigned to the geometry.

This function is the same as the CPP method OGRGeometry::transform.

Parameters:
hGeom handle on the geometry to apply the transform to.
hTransform handle on the transformation to apply.
Returns:
OGRERR_NONE on success or an error code.
OGRErr OGR_G_TransformTo ( OGRGeometryH  hGeom,
OGRSpatialReferenceH  hSRS 
)

Transform geometry to new spatial reference system.

This function will transform the coordinates of a geometry from their current spatial reference system to a new target spatial reference system. Normally this means reprojecting the vectors, but it could include datum shifts, and changes of units.

This function will only work if the geometry already has an assigned spatial reference system, and if it is transformable to the target coordinate system.

Because this function requires internal creation and initialization of an OGRCoordinateTransformation object it is significantly more expensive to use this function to transform many geometries than it is to create the OGRCoordinateTransformation in advance, and call transform() with that transformation. This function exists primarily for convenience when only transforming a single geometry.

This function is the same as the CPP method OGRGeometry::transformTo.

Parameters:
hGeom handle on the geometry to apply the transform to.
hSRS handle on the spatial reference system to apply.
Returns:
OGRERR_NONE on success, or an error code.
OGRGeometryH OGR_G_Union ( OGRGeometryH  hThis,
OGRGeometryH  hOther 
)

Compute union.

Generates a new geometry which is the region of union of the two geometries operated on.

This function is the same as the C++ method OGRGeometry::Union().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Parameters:
hThis the geometry.
hOther the other geometry.
Returns:
a new geometry representing the union or NULL if an error occurs.
OGRGeometryH OGR_G_UnionCascaded ( OGRGeometryH  hThis  ) 

Compute union using cascading.

This function is the same as the C++ method OGRGeometry::UnionCascaded().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Parameters:
hThis the geometry.
Returns:
a new geometry representing the union or NULL if an error occurs.
OGRGeometryH OGR_G_Value ( OGRGeometryH  hGeom,
double  dfDistance 
)

Fetch point at given distance along curve.

This function relates to the SF COM ICurve::get_Value() method.

This function is the same as the C++ method OGRCurve::Value().

Parameters:
hGeom curve geometry.
dfDistance distance along the curve at which to sample position. This distance should be between zero and get_Length() for this curve.
Returns:
a point or NULL.
Since:
GDAL 2.0
int OGR_G_Within ( OGRGeometryH  hThis,
OGRGeometryH  hOther 
)

Test for containment.

Tests if this geometry is within the other geometry.

This function is the same as the C++ method OGRGeometry::Within().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Parameters:
hThis the geometry to compare.
hOther the other geometry to compare.
Returns:
TRUE if hThis is within hOther, otherwise FALSE.
int OGR_G_WkbSize ( OGRGeometryH  hGeom  ) 

Returns size of related binary representation.

This function returns the exact number of bytes required to hold the well known binary representation of this geometry object. Its computation may be slightly expensive for complex geometries.

This function relates to the SFCOM IWks::WkbSize() method.

This function is the same as the CPP method OGRGeometry::WkbSize().

Parameters:
hGeom handle on the geometry to get the binary size from.
Returns:
size of binary representation in bytes.
const char* OGR_GetFieldSubTypeName ( OGRFieldSubType  eSubType  ) 

Fetch human readable name for a field subtype.

This function is the same as the CPP method OGRFieldDefn::GetFieldSubTypeName().

Parameters:
eSubType the field subtype to get name for.
Returns:
the name.
Since:
GDAL 2.0
const char* OGR_GetFieldTypeName ( OGRFieldType  eType  ) 

Fetch human readable name for a field type.

This function is the same as the CPP method OGRFieldDefn::GetFieldTypeName().

Parameters:
eType the field type to get name for.
Returns:
the name.
OGRGeomFieldDefnH OGR_GFld_Create ( const char *  pszName,
OGRwkbGeometryType  eType 
)

Create a new field geometry definition.

This function is the same as the CPP method OGRGeomFieldDefn::OGRGeomFieldDefn().

Parameters:
pszName the name of the new field definition.
eType the type of the new field definition.
Returns:
handle to the new field definition.
Since:
GDAL 1.11
void OGR_GFld_Destroy ( OGRGeomFieldDefnH  hDefn  ) 

Destroy a geometry field definition.

Parameters:
hDefn handle to the geometry field definition to destroy.
Since:
GDAL 1.11
const char* OGR_GFld_GetNameRef ( OGRGeomFieldDefnH  hDefn  ) 

Fetch name of this field.

This function is the same as the CPP method OGRGeomFieldDefn::GetNameRef().

Parameters:
hDefn handle to the geometry field definition.
Returns:
the name of the geometry field definition.
Since:
GDAL 1.11
OGRSpatialReferenceH OGR_GFld_GetSpatialRef ( OGRGeomFieldDefnH  hDefn  ) 

Fetch spatial reference system of this field.

This function is the same as the C++ method OGRGeomFieldDefn::GetSpatialRef().

Parameters:
hDefn handle to the geometry field definition
Returns:
field spatial reference system.
Since:
GDAL 1.11
OGRwkbGeometryType OGR_GFld_GetType ( OGRGeomFieldDefnH  hDefn  ) 

Fetch geometry type of this field.

This function is the same as the CPP method OGRGeomFieldDefn::GetType().

Parameters:
hDefn handle to the geometry field definition to get type from.
Returns:
field geometry type.
Since:
GDAL 1.11
int OGR_GFld_IsIgnored ( OGRGeomFieldDefnH  hDefn  ) 

Return whether this field should be omitted when fetching features.

This method is the same as the C++ method OGRGeomFieldDefn::IsIgnored().

Parameters:
hDefn handle to the geometry field definition
Returns:
ignore state
Since:
GDAL 1.11
void OGR_GFld_SetIgnored ( OGRGeomFieldDefnH  hDefn,
int  ignore 
)

Set whether this field should be omitted when fetching features.

This method is the same as the C++ method OGRGeomFieldDefn::SetIgnored().

Parameters:
hDefn handle to the geometry field definition
ignore ignore state
Since:
GDAL 1.11
void OGR_GFld_SetName ( OGRGeomFieldDefnH  hDefn,
const char *  pszName 
)

Reset the name of this field.

This function is the same as the CPP method OGRGeomFieldDefn::SetName().

Parameters:
hDefn handle to the geometry field definition to apply the new name to.
pszName the new name to apply.
Since:
GDAL 1.11
void OGR_GFld_SetSpatialRef ( OGRGeomFieldDefnH  hDefn,
OGRSpatialReferenceH  hSRS 
)

Set the spatial reference of this field.

This function is the same as the C++ method OGRGeomFieldDefn::SetSpatialRef().

This function drops the reference of the previously set SRS object and acquires a new reference on the passed object (if non-NULL).

Parameters:
hDefn handle to the geometry field definition
hSRS the new SRS to apply.
Since:
GDAL 1.11
void OGR_GFld_SetType ( OGRGeomFieldDefnH  hDefn,
OGRwkbGeometryType  eType 
)

Set the geometry type of this field.

This should never be done to an OGRGeomFieldDefn that is already part of an OGRFeatureDefn.

This function is the same as the CPP method OGRGeomFieldDefn::SetType().

Parameters:
hDefn handle to the geometry field definition to set type to.
eType the new field geometry type.
Since:
GDAL 1.11
OGRErr OGR_L_AlterFieldDefn ( OGRLayerH  hLayer,
int  iField,
OGRFieldDefnH  hNewFieldDefn,
int  nFlags 
)

Alter the definition of an existing field on a layer.

You must use this to alter the definition of an existing field of a real layer. Internally the OGRFeatureDefn for the layer will be updated to reflect the altered field. Applications should never modify the OGRFeatureDefn used by a layer directly.

This function should not be called while there are feature objects in existance that were obtained or created with the previous layer definition.

Not all drivers support this function. You can query a layer to check if it supports it with the OLCAlterFieldDefn capability. Some drivers may only support this method while there are still no features in the layer. When it is supported, the existings features of the backing file/database should be updated accordingly. Some drivers might also not support all update flags.

This function is the same as the C++ method OGRLayer::AlterFieldDefn().

Parameters:
hLayer handle to the layer.
iField index of the field whose definition must be altered.
hNewFieldDefn new field definition
nFlags combination of ALTER_NAME_FLAG, ALTER_TYPE_FLAG and ALTER_WIDTH_PRECISION_FLAG to indicate which of the name and/or type and/or width and precision fields from the new field definition must be taken into account.
Returns:
OGRERR_NONE on success.
Since:
OGR 1.9.0
OGRErr OGR_L_Clip ( OGRLayerH  pLayerInput,
OGRLayerH  pLayerMethod,
OGRLayerH  pLayerResult,
char **  papszOptions,
GDALProgressFunc  pfnProgress,
void *  pProgressArg 
)

Clip off areas that are not covered by the method layer.

The result layer contains features whose geometries represent areas that are in the input layer and in the method layer. The features in the result layer have the (possibly clipped) areas of features in the input layer and the attributes from the same features. The schema of the result layer can be set by the user or, if it is empty, is initialized to contain all fields in the input layer.

Note:
For best performance use the minimum amount of features in the method layer and copy it into a memory layer.
This method relies on GEOS support. Do not use unless the GEOS support is compiled in.

The recognized list of options is :

  • SKIP_FAILURES=YES/NO. Set it to YES to go on, even when a feature could not be inserted.
  • PROMOTE_TO_MULTI=YES/NO. Set it to YES to convert Polygons into MultiPolygons, or LineStrings to MultiLineStrings.
  • INPUT_PREFIX=string. Set a prefix for the field names that will be created from the fields of the input layer.
  • METHOD_PREFIX=string. Set a prefix for the field names that will be created from the fields of the method layer.

This function is the same as the C++ method OGRLayer::Clip().

Parameters:
pLayerInput the input layer. Should not be NULL.
pLayerMethod the method layer. Should not be NULL.
pLayerResult the layer where the features resulting from the operation are inserted. Should not be NULL. See above the note about the schema.
papszOptions NULL terminated list of options (may be NULL).
pfnProgress a GDALProgressFunc() compatible callback function for reporting progress or NULL.
pProgressArg argument to be passed to pfnProgress. May be NULL.
Returns:
an error code if there was an error or the execution was interrupted, OGRERR_NONE otherwise.
Since:
OGR 1.10
OGRErr OGR_L_CommitTransaction ( OGRLayerH  hLayer  ) 

For datasources which support transactions, CommitTransaction commits a transaction.

If no transaction is active, or the commit fails, will return OGRERR_FAILURE. Datasources which do not support transactions will always return OGRERR_NONE.

This function is the same as the C++ method OGRLayer::CommitTransaction().

Parameters:
hLayer handle to the layer
Returns:
OGRERR_NONE on success.
OGRErr OGR_L_CreateFeature ( OGRLayerH  hLayer,
OGRFeatureH  hFeat 
)

Create and write a new feature within a layer.

The passed feature is written to the layer as a new feature, rather than overwriting an existing one. If the feature has a feature id other than OGRNullFID, then the native implementation may use that as the feature id of the new feature, but not necessarily. Upon successful return the passed feature will have been updated with the new feature id.

This function is the same as the C++ method OGRLayer::CreateFeature().

Parameters:
hLayer handle to the layer to write the feature to.
hFeat the handle of the feature to write to disk.
Returns:
OGRERR_NONE on success.
OGRErr OGR_L_CreateField ( OGRLayerH  hLayer,
OGRFieldDefnH  hField,
int  bApproxOK 
)

Create a new field on a layer.

You must use this to create new fields on a real layer. Internally the OGRFeatureDefn for the layer will be updated to reflect the new field. Applications should never modify the OGRFeatureDefn used by a layer directly.

This function should not be called while there are feature objects in existance that were obtained or created with the previous layer definition.

Not all drivers support this function. You can query a layer to check if it supports it with the OLCCreateField capability. Some drivers may only support this method while there are still no features in the layer. When it is supported, the existings features of the backing file/database should be updated accordingly.

This function is the same as the C++ method OGRLayer::CreateField().

Parameters:
hLayer handle to the layer to write the field definition.
hField handle of the field definition to write to disk.
bApproxOK If TRUE, the field may be created in a slightly different form depending on the limitations of the format driver.
Returns:
OGRERR_NONE on success.
OGRErr OGR_L_CreateGeomField ( OGRLayerH  hLayer,
OGRGeomFieldDefnH  hField,
int  bApproxOK 
)

Create a new geometry field on a layer.

You must use this to create new geometry fields on a real layer. Internally the OGRFeatureDefn for the layer will be updated to reflect the new field. Applications should never modify the OGRFeatureDefn used by a layer directly.

This function should not be called while there are feature objects in existance that were obtained or created with the previous layer definition.

Not all drivers support this function. You can query a layer to check if it supports it with the OLCCreateField capability. Some drivers may only support this method while there are still no features in the layer. When it is supported, the existings features of the backing file/database should be updated accordingly.

This function is the same as the C++ method OGRLayer::CreateField().

Parameters:
hLayer handle to the layer to write the field definition.
hField handle of the geometry field definition to write to disk.
bApproxOK If TRUE, the field may be created in a slightly different form depending on the limitations of the format driver.
Returns:
OGRERR_NONE on success.
Since:
OGR 1.11
OGRErr OGR_L_DeleteFeature ( OGRLayerH  hLayer,
long  nFID 
)

Delete feature from layer.

The feature with the indicated feature id is deleted from the layer if supported by the driver. Most drivers do not support feature deletion, and will return OGRERR_UNSUPPORTED_OPERATION. The OGR_L_TestCapability() function may be called with OLCDeleteFeature to check if the driver supports feature deletion.

This method is the same as the C++ method OGRLayer::DeleteFeature().

Parameters:
hLayer handle to the layer
nFID the feature id to be deleted from the layer
Returns:
OGRERR_NONE on success.
OGRErr OGR_L_DeleteField ( OGRLayerH  hLayer,
int  iField 
)

Create a new field on a layer.

You must use this to delete existing fields on a real layer. Internally the OGRFeatureDefn for the layer will be updated to reflect the deleted field. Applications should never modify the OGRFeatureDefn used by a layer directly.

This function should not be called while there are feature objects in existance that were obtained or created with the previous layer definition.

Not all drivers support this function. You can query a layer to check if it supports it with the OLCDeleteField capability. Some drivers may only support this method while there are still no features in the layer. When it is supported, the existings features of the backing file/database should be updated accordingly.

This function is the same as the C++ method OGRLayer::DeleteField().

Parameters:
hLayer handle to the layer.
iField index of the field to delete.
Returns:
OGRERR_NONE on success.
Since:
OGR 1.9.0
OGRErr OGR_L_Erase ( OGRLayerH  pLayerInput,
OGRLayerH  pLayerMethod,
OGRLayerH  pLayerResult,
char **  papszOptions,
GDALProgressFunc  pfnProgress,
void *  pProgressArg 
)

Remove areas that are covered by the method layer.

The result layer contains features whose geometries represent areas that are in the input layer but not in the method layer. The features in the result layer have attributes from the input layer. The schema of the result layer can be set by the user or, if it is empty, is initialized to contain all fields in the input layer.

Note:
For best performance use the minimum amount of features in the method layer and copy it into a memory layer.
This method relies on GEOS support. Do not use unless the GEOS support is compiled in.

The recognized list of options is :

  • SKIP_FAILURES=YES/NO. Set it to YES to go on, even when a feature could not be inserted.
  • PROMOTE_TO_MULTI=YES/NO. Set it to YES to convert Polygons into MultiPolygons, or LineStrings to MultiLineStrings.
  • INPUT_PREFIX=string. Set a prefix for the field names that will be created from the fields of the input layer.
  • METHOD_PREFIX=string. Set a prefix for the field names that will be created from the fields of the method layer.

This function is the same as the C++ method OGRLayer::Erase().

Parameters:
pLayerInput the input layer. Should not be NULL.
pLayerMethod the method layer. Should not be NULL.
pLayerResult the layer where the features resulting from the operation are inserted. Should not be NULL. See above the note about the schema.
papszOptions NULL terminated list of options (may be NULL).
pfnProgress a GDALProgressFunc() compatible callback function for reporting progress or NULL.
pProgressArg argument to be passed to pfnProgress. May be NULL.
Returns:
an error code if there was an error or the execution was interrupted, OGRERR_NONE otherwise.
Since:
OGR 1.10
int OGR_L_FindFieldIndex ( OGRLayerH  hLayer,
const char *  ,
int  bExactMatch 
)

Find the index of field in a layer.

The returned number is the index of the field in the layers, or -1 if the field doesn't exist.

If bExactMatch is set to FALSE and the field doesn't exists in the given form the driver might apply some changes to make it match, like those it might do if the layer was created (eg. like LAUNDER in the OCI driver).

This method is the same as the C++ method OGRLayer::FindFieldIndex().

Returns:
field index, or -1 if the field doesn't exist
OGRErr OGR_L_GetExtent ( OGRLayerH  hLayer,
OGREnvelope psExtent,
int  bForce 
)

Fetch the extent of this layer.

Returns the extent (MBR) of the data in the layer. If bForce is FALSE, and it would be expensive to establish the extent then OGRERR_FAILURE will be returned indicating that the extent isn't know. If bForce is TRUE then some implementations will actually scan the entire layer once to compute the MBR of all the features in the layer.

Depending on the drivers, the returned extent may or may not take the spatial filter into account. So it is safer to call OGR_L_GetExtent() without setting a spatial filter.

Layers without any geometry may return OGRERR_FAILURE just indicating that no meaningful extents could be collected.

Note that some implementations of this method may alter the read cursor of the layer.

This function is the same as the C++ method OGRLayer::GetExtent().

Parameters:
hLayer handle to the layer from which to get extent.
psExtent the structure in which the extent value will be returned.
bForce Flag indicating whether the extent should be computed even if it is expensive.
Returns:
OGRERR_NONE on success, OGRERR_FAILURE if extent not known.
OGRErr OGR_L_GetExtentEx ( OGRLayerH  hLayer,
int  iGeomField,
OGREnvelope psExtent,
int  bForce 
)

Fetch the extent of this layer, on the specified geometry field.

Returns the extent (MBR) of the data in the layer. If bForce is FALSE, and it would be expensive to establish the extent then OGRERR_FAILURE will be returned indicating that the extent isn't know. If bForce is TRUE then some implementations will actually scan the entire layer once to compute the MBR of all the features in the layer.

Depending on the drivers, the returned extent may or may not take the spatial filter into account. So it is safer to call OGR_L_GetExtent() without setting a spatial filter.

Layers without any geometry may return OGRERR_FAILURE just indicating that no meaningful extents could be collected.

Note that some implementations of this method may alter the read cursor of the layer.

This function is the same as the C++ method OGRLayer::GetExtent().

Parameters:
hLayer handle to the layer from which to get extent.
iGeomField the index of the geometry field on which to compute the extent.
psExtent the structure in which the extent value will be returned.
bForce Flag indicating whether the extent should be computed even if it is expensive.
Returns:
OGRERR_NONE on success, OGRERR_FAILURE if extent not known.
OGRFeatureH OGR_L_GetFeature ( OGRLayerH  hLayer,
long  nFeatureId 
)

Fetch a feature by its identifier.

This function will attempt to read the identified feature. The nFID value cannot be OGRNullFID. Success or failure of this operation is unaffected by the spatial or attribute filters (and specialized implementations in drivers should make sure that they do not take into account spatial or attribute filters).

If this function returns a non-NULL feature, it is guaranteed that its feature id (OGR_F_GetFID()) will be the same as nFID.

Use OGR_L_TestCapability(OLCRandomRead) to establish if this layer supports efficient random access reading via OGR_L_GetFeature(); however, the call should always work if the feature exists as a fallback implementation just scans all the features in the layer looking for the desired feature.

Sequential reads (with OGR_L_GetNextFeature()) are generally considered interrupted by a OGR_L_GetFeature() call.

The returned feature should be free with OGR_F_Destroy().

This function is the same as the C++ method OGRLayer::GetFeature( ).

Parameters:
hLayer handle to the layer that owned the feature.
nFeatureId the feature id of the feature to read.
Returns:
an handle to a feature now owned by the caller, or NULL on failure.
int OGR_L_GetFeatureCount ( OGRLayerH  hLayer,
int  bForce 
)

Fetch the feature count in this layer.

Returns the number of features in the layer. For dynamic databases the count may not be exact. If bForce is FALSE, and it would be expensive to establish the feature count a value of -1 may be returned indicating that the count isn't know. If bForce is TRUE some implementations will actually scan the entire layer once to count objects.

The returned count takes the spatial filter into account.

Note that some implementations of this method may alter the read cursor of the layer.

This function is the same as the CPP OGRLayer::GetFeatureCount().

Parameters:
hLayer handle to the layer that owned the features.
bForce Flag indicating whether the count should be computed even if it is expensive.
Returns:
feature count, -1 if count not known.
const char * OGR_L_GetFIDColumn ( OGRLayerH  hLayer  ) 

This method returns the name of the underlying database column being used as the FID column, or "" if not supported.

This method is the same as the C++ method OGRLayer::GetFIDColumn()

Parameters:
hLayer handle to the layer
Returns:
fid column name.
const char * OGR_L_GetGeometryColumn ( OGRLayerH  hLayer  ) 

This method returns the name of the underlying database column being used as the geometry column, or "" if not supported.

This method is the same as the C++ method OGRLayer::GetGeometryColumn()

Parameters:
hLayer handle to the layer
Returns:
geometry column name.
OGRwkbGeometryType OGR_L_GetGeomType ( OGRLayerH  hLayer  ) 

Return the layer geometry type.

This returns the same result as OGR_FD_GetGeomType(OGR_L_GetLayerDefn(hLayer)), but for a few drivers, calling OGR_L_GetGeomType() directly can avoid lengthy layer definition initialization.

This function is the same as the C++ method OGRLayer::GetGeomType().

Parameters:
hLayer handle to the layer.
Returns:
the geometry type
Since:
OGR 1.8.0
OGRFeatureDefnH OGR_L_GetLayerDefn ( OGRLayerH  hLayer  ) 

Fetch the schema information for this layer.

The returned handle to the OGRFeatureDefn is owned by the OGRLayer, and should not be modified or freed by the application. It encapsulates the attribute schema of the features of the layer.

This function is the same as the C++ method OGRLayer::GetLayerDefn().

Parameters:
hLayer handle to the layer to get the schema information.
Returns:
an handle to the feature definition.
const char * OGR_L_GetName ( OGRLayerH  hLayer  ) 

Return the layer name.

This returns the same content as OGR_FD_GetName(OGR_L_GetLayerDefn(hLayer)), but for a few drivers, calling OGR_L_GetName() directly can avoid lengthy layer definition initialization.

This function is the same as the C++ method OGRLayer::GetName().

Parameters:
hLayer handle to the layer.
Returns:
the layer name (must not been freed)
Since:
OGR 1.8.0
OGRFeatureH OGR_L_GetNextFeature ( OGRLayerH  hLayer  ) 

Fetch the next available feature from this layer.

The returned feature becomes the responsiblity of the caller to delete with OGR_F_Destroy(). It is critical that all features associated with an OGRLayer (more specifically an OGRFeatureDefn) be deleted before that layer/datasource is deleted.

Only features matching the current spatial filter (set with SetSpatialFilter()) will be returned.

This function implements sequential access to the features of a layer. The OGR_L_ResetReading() function can be used to start at the beginning again.

This function is the same as the C++ method OGRLayer::GetNextFeature().

Parameters:
hLayer handle to the layer from which feature are read.
Returns:
an handle to a feature, or NULL if no more features are available.
OGRGeometryH OGR_L_GetSpatialFilter ( OGRLayerH  hLayer  ) 

This function returns the current spatial filter for this layer.

The returned pointer is to an internally owned object, and should not be altered or deleted by the caller.

This function is the same as the C++ method OGRLayer::GetSpatialFilter().

Parameters:
hLayer handle to the layer to get the spatial filter from.
Returns:
an handle to the spatial filter geometry.
OGRSpatialReferenceH OGR_L_GetSpatialRef ( OGRLayerH  hLayer  ) 

Fetch the spatial reference system for this layer.

The returned object is owned by the OGRLayer and should not be modified or freed by the application.

This function is the same as the C++ method OGRLayer::GetSpatialRef().

Parameters:
hLayer handle to the layer to get the spatial reference from.
Returns:
spatial reference, or NULL if there isn't one.
OGRErr OGR_L_Identity ( OGRLayerH  pLayerInput,
OGRLayerH  pLayerMethod,
OGRLayerH  pLayerResult,
char **  papszOptions,
GDALProgressFunc  pfnProgress,
void *  pProgressArg 
)

Identify the features of this layer with the ones from the identity layer.

The result layer contains features whose geometries represent areas that are in the input layer. The features in the result layer have attributes from both input and method layers. The schema of the result layer can be set by the user or, if it is empty, is initialized to contain all fields in input and method layers.

Note:
If the schema of the result is set by user and contains fields that have the same name as a field in input and in method layer, then the attribute in the result feature will get the value from the feature of the method layer (even if it is undefined).
For best performance use the minimum amount of features in the method layer and copy it into a memory layer.
This method relies on GEOS support. Do not use unless the GEOS support is compiled in.

The recognized list of options is :

  • SKIP_FAILURES=YES/NO. Set it to YES to go on, even when a feature could not be inserted.
  • PROMOTE_TO_MULTI=YES/NO. Set it to YES to convert Polygons into MultiPolygons, or LineStrings to MultiLineStrings.
  • INPUT_PREFIX=string. Set a prefix for the field names that will be created from the fields of the input layer.
  • METHOD_PREFIX=string. Set a prefix for the field names that will be created from the fields of the method layer.

This function is the same as the C++ method OGRLayer::Identity().

Parameters:
pLayerInput the input layer. Should not be NULL.
pLayerMethod the method layer. Should not be NULL.
pLayerResult the layer where the features resulting from the operation are inserted. Should not be NULL. See above the note about the schema.
papszOptions NULL terminated list of options (may be NULL).
pfnProgress a GDALProgressFunc() compatible callback function for reporting progress or NULL.
pProgressArg argument to be passed to pfnProgress. May be NULL.
Returns:
an error code if there was an error or the execution was interrupted, OGRERR_NONE otherwise.
Since:
OGR 1.10
OGRErr OGR_L_Intersection ( OGRLayerH  pLayerInput,
OGRLayerH  pLayerMethod,
OGRLayerH  pLayerResult,
char **  papszOptions,
GDALProgressFunc  pfnProgress,
void *  pProgressArg 
)

Intersection of two layers.

The result layer contains features whose geometries represent areas that are common between features in the input layer and in the method layer. The features in the result layer have attributes from both input and method layers. The schema of the result layer can be set by the user or, if it is empty, is initialized to contain all fields in the input and method layers.

Note:
If the schema of the result is set by user and contains fields that have the same name as a field in input and in method layer, then the attribute in the result feature will get the value from the feature of the method layer.
For best performance use the minimum amount of features in the method layer and copy it into a memory layer.
This method relies on GEOS support. Do not use unless the GEOS support is compiled in.

The recognized list of options is :

  • SKIP_FAILURES=YES/NO. Set it to YES to go on, even when a feature could not be inserted.
  • PROMOTE_TO_MULTI=YES/NO. Set it to YES to convert Polygons into MultiPolygons, or LineStrings to MultiLineStrings.
  • INPUT_PREFIX=string. Set a prefix for the field names that will be created from the fields of the input layer.
  • METHOD_PREFIX=string. Set a prefix for the field names that will be created from the fields of the method layer.

This function is the same as the C++ method OGRLayer::Intersection().

Parameters:
pLayerInput the input layer. Should not be NULL.
pLayerMethod the method layer. Should not be NULL.
pLayerResult the layer where the features resulting from the operation are inserted. Should not be NULL. See above the note about the schema.
papszOptions NULL terminated list of options (may be NULL).
pfnProgress a GDALProgressFunc() compatible callback function for reporting progress or NULL.
pProgressArg argument to be passed to pfnProgress. May be NULL.
Returns:
an error code if there was an error or the execution was interrupted, OGRERR_NONE otherwise.
Since:
OGR 1.10
OGRErr OGR_L_ReorderField ( OGRLayerH  hLayer,
int  iOldFieldPos,
int  iNewFieldPos 
)

Reorder an existing field on a layer.

This function is a conveniency wrapper of OGR_L_ReorderFields() dedicated to move a single field.

You must use this to reorder existing fields on a real layer. Internally the OGRFeatureDefn for the layer will be updated to reflect the reordering of the fields. Applications should never modify the OGRFeatureDefn used by a layer directly.

This function should not be called while there are feature objects in existance that were obtained or created with the previous layer definition.

The field definition that was at initial position iOldFieldPos will be moved at position iNewFieldPos, and elements between will be shuffled accordingly.

For example, let suppose the fields were "0","1","2","3","4" initially. ReorderField(1, 3) will reorder them as "0","2","3","1","4".

Not all drivers support this function. You can query a layer to check if it supports it with the OLCReorderFields capability. Some drivers may only support this method while there are still no features in the layer. When it is supported, the existings features of the backing file/database should be updated accordingly.

This function is the same as the C++ method OGRLayer::ReorderField().

Parameters:
hLayer handle to the layer.
iOldFieldPos previous position of the field to move. Must be in the range [0,GetFieldCount()-1].
iNewFieldPos new position of the field to move. Must be in the range [0,GetFieldCount()-1].
Returns:
OGRERR_NONE on success.
Since:
OGR 1.9.0
OGRErr OGR_L_ReorderFields ( OGRLayerH  hLayer,
int *  panMap 
)

Reorder all the fields of a layer.

You must use this to reorder existing fields on a real layer. Internally the OGRFeatureDefn for the layer will be updated to reflect the reordering of the fields. Applications should never modify the OGRFeatureDefn used by a layer directly.

This function should not be called while there are feature objects in existance that were obtained or created with the previous layer definition.

panMap is such that,for each field definition at position i after reordering, its position before reordering was panMap[i].

For example, let suppose the fields were "0","1","2","3","4" initially. ReorderFields([0,2,3,1,4]) will reorder them as "0","2","3","1","4".

Not all drivers support this function. You can query a layer to check if it supports it with the OLCReorderFields capability. Some drivers may only support this method while there are still no features in the layer. When it is supported, the existings features of the backing file/database should be updated accordingly.

This function is the same as the C++ method OGRLayer::ReorderFields().

Parameters:
hLayer handle to the layer.
panMap an array of GetLayerDefn()->GetFieldCount() elements which is a permutation of [0, GetLayerDefn()->GetFieldCount()-1].
Returns:
OGRERR_NONE on success.
Since:
OGR 1.9.0
void OGR_L_ResetReading ( OGRLayerH  hLayer  ) 

Reset feature reading to start on the first feature.

This affects GetNextFeature().

This function is the same as the C++ method OGRLayer::ResetReading().

Parameters:
hLayer handle to the layer on which features are read.
OGRErr OGR_L_RollbackTransaction ( OGRLayerH  hLayer  ) 

For datasources which support transactions, RollbackTransaction will roll back a datasource to its state before the start of the current transaction.

If no transaction is active, or the rollback fails, will return OGRERR_FAILURE. Datasources which do not support transactions will always return OGRERR_NONE.

This function is the same as the C++ method OGRLayer::RollbackTransaction().

Parameters:
hLayer handle to the layer
Returns:
OGRERR_NONE on success.
OGRErr OGR_L_SetAttributeFilter ( OGRLayerH  hLayer,
const char *  pszQuery 
)

Set a new attribute query.

This function sets the attribute query string to be used when fetching features via the OGR_L_GetNextFeature() function. Only features for which the query evaluates as true will be returned.

The query string should be in the format of an SQL WHERE clause. For instance "population > 1000000 and population < 5000000" where population is an attribute in the layer. The query format is a restricted form of SQL WHERE clause as defined "eq_format=restricted_where" about half way through this document:

http://ogdi.sourceforge.net/prop/6.2.CapabilitiesMetadata.html

Note that installing a query string will generally result in resetting the current reading position (ala OGR_L_ResetReading()).

This function is the same as the C++ method OGRLayer::SetAttributeFilter().

Parameters:
hLayer handle to the layer on which attribute query will be executed.
pszQuery query in restricted SQL WHERE format, or NULL to clear the current query.
Returns:
OGRERR_NONE if successfully installed, or an error code if the query expression is in error, or some other failure occurs.
OGRErr OGR_L_SetFeature ( OGRLayerH  hLayer,
OGRFeatureH  hFeat 
)

Rewrite an existing feature.

This function will write a feature to the layer, based on the feature id within the OGRFeature.

Use OGR_L_TestCapability(OLCRandomWrite) to establish if this layer supports random access writing via OGR_L_SetFeature().

This function is the same as the C++ method OGRLayer::SetFeature().

Parameters:
hLayer handle to the layer to write the feature.
hFeat the feature to write.
Returns:
OGRERR_NONE if the operation works, otherwise an appropriate error code.
OGRErr OGR_L_SetIgnoredFields ( OGRLayerH  ,
const char **  papszFields 
)

Set which fields can be omitted when retrieving features from the layer.

If the driver supports this functionality (testable using OLCIgnoreFields capability), it will not fetch the specified fields in subsequent calls to GetFeature() / GetNextFeature() and thus save some processing time and/or bandwidth.

Besides field names of the layers, the following special fields can be passed: "OGR_GEOMETRY" to ignore geometry and "OGR_STYLE" to ignore layer style.

By default, no fields are ignored.

This method is the same as the C++ method OGRLayer::SetIgnoredFields()

Parameters:
papszFields an array of field names terminated by NULL item. If NULL is passed, the ignored list is cleared.
Returns:
OGRERR_NONE if all field names have been resolved (even if the driver does not support this method)
OGRErr OGR_L_SetNextByIndex ( OGRLayerH  hLayer,
long  nIndex 
)

Move read cursor to the nIndex'th feature in the current resultset.

This method allows positioning of a layer such that the GetNextFeature() call will read the requested feature, where nIndex is an absolute index into the current result set. So, setting it to 3 would mean the next feature read with GetNextFeature() would have been the 4th feature to have been read if sequential reading took place from the beginning of the layer, including accounting for spatial and attribute filters.

Only in rare circumstances is SetNextByIndex() efficiently implemented. In all other cases the default implementation which calls ResetReading() and then calls GetNextFeature() nIndex times is used. To determine if fast seeking is available on the current layer use the TestCapability() method with a value of OLCFastSetNextByIndex.

This method is the same as the C++ method OGRLayer::SetNextByIndex()

Parameters:
hLayer handle to the layer
nIndex the index indicating how many steps into the result set to seek.
Returns:
OGRERR_NONE on success or an error code.
void OGR_L_SetSpatialFilter ( OGRLayerH  hLayer,
OGRGeometryH  hGeom 
)

Set a new spatial filter.

This function set the geometry to be used as a spatial filter when fetching features via the OGR_L_GetNextFeature() function. Only features that geometrically intersect the filter geometry will be returned.

Currently this test is may be inaccurately implemented, but it is guaranteed that all features who's envelope (as returned by OGR_G_GetEnvelope()) overlaps the envelope of the spatial filter will be returned. This can result in more shapes being returned that should strictly be the case.

This function makes an internal copy of the passed geometry. The passed geometry remains the responsibility of the caller, and may be safely destroyed.

For the time being the passed filter geometry should be in the same SRS as the layer (as returned by OGR_L_GetSpatialRef()). In the future this may be generalized.

This function is the same as the C++ method OGRLayer::SetSpatialFilter.

Parameters:
hLayer handle to the layer on which to set the spatial filter.
hGeom handle to the geometry to use as a filtering region. NULL may be passed indicating that the current spatial filter should be cleared, but no new one instituted.
void OGR_L_SetSpatialFilterEx ( OGRLayerH  hLayer,
int  iGeomField,
OGRGeometryH  hGeom 
)

Set a new spatial filter.

This function set the geometry to be used as a spatial filter when fetching features via the OGR_L_GetNextFeature() function. Only features that geometrically intersect the filter geometry will be returned.

Currently this test is may be inaccurately implemented, but it is guaranteed that all features who's envelope (as returned by OGR_G_GetEnvelope()) overlaps the envelope of the spatial filter will be returned. This can result in more shapes being returned that should strictly be the case.

This function makes an internal copy of the passed geometry. The passed geometry remains the responsibility of the caller, and may be safely destroyed.

For the time being the passed filter geometry should be in the same SRS as the geometry field definition it corresponds to (as returned by GetLayerDefn()->GetGeomFieldDefn(iGeomField)->GetSpatialRef()). In the future this may be generalized.

Note that only the last spatial filter set is applied, even if several successive calls are done with different iGeomField values.

This function is the same as the C++ method OGRLayer::SetSpatialFilter.

Parameters:
hLayer handle to the layer on which to set the spatial filter.
iGeomField index of the geometry field on which the spatial filter operates.
hGeom handle to the geometry to use as a filtering region. NULL may be passed indicating that the current spatial filter should be cleared, but no new one instituted.
Since:
GDAL 1.11
void OGR_L_SetSpatialFilterRect ( OGRLayerH  hLayer,
double  dfMinX,
double  dfMinY,
double  dfMaxX,
double  dfMaxY 
)

Set a new rectangular spatial filter.

This method set rectangle to be used as a spatial filter when fetching features via the OGR_L_GetNextFeature() method. Only features that geometrically intersect the given rectangle will be returned.

The x/y values should be in the same coordinate system as the layer as a whole (as returned by OGRLayer::GetSpatialRef()). Internally this method is normally implemented as creating a 5 vertex closed rectangular polygon and passing it to OGRLayer::SetSpatialFilter(). It exists as a convenience.

The only way to clear a spatial filter set with this method is to call OGRLayer::SetSpatialFilter(NULL).

This method is the same as the C++ method OGRLayer::SetSpatialFilterRect().

Parameters:
hLayer handle to the layer on which to set the spatial filter.
dfMinX the minimum X coordinate for the rectangular region.
dfMinY the minimum Y coordinate for the rectangular region.
dfMaxX the maximum X coordinate for the rectangular region.
dfMaxY the maximum Y coordinate for the rectangular region.
void OGR_L_SetSpatialFilterRectEx ( OGRLayerH  hLayer,
int  iGeomField,
double  dfMinX,
double  dfMinY,
double  dfMaxX,
double  dfMaxY 
)

Set a new rectangular spatial filter.

This method set rectangle to be used as a spatial filter when fetching features via the OGR_L_GetNextFeature() method. Only features that geometrically intersect the given rectangle will be returned.

The x/y values should be in the same coordinate system as as the geometry field definition it corresponds to (as returned by GetLayerDefn()->GetGeomFieldDefn(iGeomField)->GetSpatialRef()). Internally this method is normally implemented as creating a 5 vertex closed rectangular polygon and passing it to OGRLayer::SetSpatialFilter(). It exists as a convenience.

The only way to clear a spatial filter set with this method is to call OGRLayer::SetSpatialFilter(NULL).

This method is the same as the C++ method OGRLayer::SetSpatialFilterRect().

Parameters:
hLayer handle to the layer on which to set the spatial filter.
iGeomField index of the geometry field on which the spatial filter operates.
dfMinX the minimum X coordinate for the rectangular region.
dfMinY the minimum Y coordinate for the rectangular region.
dfMaxX the maximum X coordinate for the rectangular region.
dfMaxY the maximum Y coordinate for the rectangular region.
Since:
GDAL 1.11
OGRErr OGR_L_StartTransaction ( OGRLayerH  hLayer  ) 

For datasources which support transactions, StartTransaction creates a transaction.

If starting the transaction fails, will return OGRERR_FAILURE. Datasources which do not support transactions will always return OGRERR_NONE.

This function is the same as the C++ method OGRLayer::StartTransaction().

Parameters:
hLayer handle to the layer
Returns:
OGRERR_NONE on success.
OGRErr OGR_L_SymDifference ( OGRLayerH  pLayerInput,
OGRLayerH  pLayerMethod,
OGRLayerH  pLayerResult,
char **  papszOptions,
GDALProgressFunc  pfnProgress,
void *  pProgressArg 
)

Symmetrical difference of two layers.

The result layer contains features whose geometries represent areas that are in either in the input layer or in the method layer but not in both. The features in the result layer have attributes from both input and method layers. For features which represent areas that are only in the input or in the method layer the respective attributes have undefined values. The schema of the result layer can be set by the user or, if it is empty, is initialized to contain all fields in the input and method layers.

Note:
If the schema of the result is set by user and contains fields that have the same name as a field in input and in method layer, then the attribute in the result feature will get the value from the feature of the method layer (even if it is undefined).
For best performance use the minimum amount of features in the method layer and copy it into a memory layer.
This method relies on GEOS support. Do not use unless the GEOS support is compiled in.

The recognized list of options is :

  • SKIP_FAILURES=YES/NO. Set it to YES to go on, even when a feature could not be inserted.
  • PROMOTE_TO_MULTI=YES/NO. Set it to YES to convert Polygons into MultiPolygons, or LineStrings to MultiLineStrings.
  • INPUT_PREFIX=string. Set a prefix for the field names that will be created from the fields of the input layer.
  • METHOD_PREFIX=string. Set a prefix for the field names that will be created from the fields of the method layer.

This function is the same as the C++ method OGRLayer::SymDifference().

Parameters:
pLayerInput the input layer. Should not be NULL.
pLayerMethod the method layer. Should not be NULL.
pLayerResult the layer where the features resulting from the operation are inserted. Should not be NULL. See above the note about the schema.
papszOptions NULL terminated list of options (may be NULL).
pfnProgress a GDALProgressFunc() compatible callback function for reporting progress or NULL.
pProgressArg argument to be passed to pfnProgress. May be NULL.
Returns:
an error code if there was an error or the execution was interrupted, OGRERR_NONE otherwise.
Since:
OGR 1.10
OGRErr OGR_L_SyncToDisk ( OGRLayerH  hLayer  ) 

Flush pending changes to disk.

This call is intended to force the layer to flush any pending writes to disk, and leave the disk file in a consistent state. It would not normally have any effect on read-only datasources.

Some layers do not implement this method, and will still return OGRERR_NONE. The default implementation just returns OGRERR_NONE. An error is only returned if an error occurs while attempting to flush to disk.

In any event, you should always close any opened datasource with OGR_DS_Destroy() that will ensure all data is correctly flushed.

This method is the same as the C++ method OGRLayer::SyncToDisk()

Parameters:
hLayer handle to the layer
Returns:
OGRERR_NONE if no error occurs (even if nothing is done) or an error code.
int OGR_L_TestCapability ( OGRLayerH  hLayer,
const char *  pszCap 
)

Test if this layer supported the named capability.

The capability codes that can be tested are represented as strings, but #defined constants exists to ensure correct spelling. Specific layer types may implement class specific capabilities, but this can't generally be discovered by the caller.

  • OLCRandomRead / "RandomRead": TRUE if the GetFeature() method is implemented in an optimized way for this layer, as opposed to the default implementation using ResetReading() and GetNextFeature() to find the requested feature id.

  • OLCSequentialWrite / "SequentialWrite": TRUE if the CreateFeature() method works for this layer. Note this means that this particular layer is writable. The same OGRLayer class may returned FALSE for other layer instances that are effectively read-only.

  • OLCRandomWrite / "RandomWrite": TRUE if the SetFeature() method is operational on this layer. Note this means that this particular layer is writable. The same OGRLayer class may returned FALSE for other layer instances that are effectively read-only.

  • OLCFastSpatialFilter / "FastSpatialFilter": TRUE if this layer implements spatial filtering efficiently. Layers that effectively read all features, and test them with the OGRFeature intersection methods should return FALSE. This can be used as a clue by the application whether it should build and maintain its own spatial index for features in this layer.

  • OLCFastFeatureCount / "FastFeatureCount": TRUE if this layer can return a feature count (via OGR_L_GetFeatureCount()) efficiently ... ie. without counting the features. In some cases this will return TRUE until a spatial filter is installed after which it will return FALSE.

  • OLCFastGetExtent / "FastGetExtent": TRUE if this layer can return its data extent (via OGR_L_GetExtent()) efficiently ... ie. without scanning all the features. In some cases this will return TRUE until a spatial filter is installed after which it will return FALSE.

  • OLCFastSetNextByIndex / "FastSetNextByIndex": TRUE if this layer can perform the SetNextByIndex() call efficiently, otherwise FALSE.

  • OLCCreateField / "CreateField": TRUE if this layer can create new fields on the current layer using CreateField(), otherwise FALSE.

  • OLCCreateGeomField / "CreateGeomField": (GDAL >= 1.11) TRUE if this layer can create new geometry fields on the current layer using CreateGeomField(), otherwise FALSE.

  • OLCDeleteField / "DeleteField": TRUE if this layer can delete existing fields on the current layer using DeleteField(), otherwise FALSE.

  • OLCReorderFields / "ReorderFields": TRUE if this layer can reorder existing fields on the current layer using ReorderField() or ReorderFields(), otherwise FALSE.

  • OLCAlterFieldDefn / "AlterFieldDefn": TRUE if this layer can alter the definition of an existing field on the current layer using AlterFieldDefn(), otherwise FALSE.

  • OLCDeleteFeature / "DeleteFeature": TRUE if the DeleteFeature() method is supported on this layer, otherwise FALSE.

  • OLCStringsAsUTF8 / "StringsAsUTF8": TRUE if values of OFTString fields are assured to be in UTF-8 format. If FALSE the encoding of fields is uncertain, though it might still be UTF-8.

  • OLCTransactions / "Transactions": TRUE if the StartTransaction(), CommitTransaction() and RollbackTransaction() methods work in a meaningful way, otherwise FALSE.

  • OLCCurveGeometries / "CurveGeometries": TRUE if this layer supports writing curve geometries or may return such geometries. (GDAL 2.0).

This function is the same as the C++ method OGRLayer::TestCapability().

Parameters:
hLayer handle to the layer to get the capability from.
pszCap the name of the capability to test.
Returns:
TRUE if the layer has the requested capability, or FALSE otherwise. OGRLayers will return FALSE for any unrecognised capabilities.
OGRErr OGR_L_Union ( OGRLayerH  pLayerInput,
OGRLayerH  pLayerMethod,
OGRLayerH  pLayerResult,
char **  papszOptions,
GDALProgressFunc  pfnProgress,
void *  pProgressArg 
)

Union of two layers.

The result layer contains features whose geometries represent areas that are in either in the input layer or in the method layer. The features in the result layer have attributes from both input and method layers. For features which represent areas that are only in the input or in the method layer the respective attributes have undefined values. The schema of the result layer can be set by the user or, if it is empty, is initialized to contain all fields in the input and method layers.

Note:
If the schema of the result is set by user and contains fields that have the same name as a field in input and in method layer, then the attribute in the result feature will get the value from the feature of the method layer (even if it is undefined).
For best performance use the minimum amount of features in the method layer and copy it into a memory layer.
This method relies on GEOS support. Do not use unless the GEOS support is compiled in.

The recognized list of options is :

  • SKIP_FAILURES=YES/NO. Set it to YES to go on, even when a feature could not be inserted.
  • PROMOTE_TO_MULTI=YES/NO. Set it to YES to convert Polygons into MultiPolygons, or LineStrings to MultiLineStrings.
  • INPUT_PREFIX=string. Set a prefix for the field names that will be created from the fields of the input layer.
  • METHOD_PREFIX=string. Set a prefix for the field names that will be created from the fields of the method layer.

This function is the same as the C++ method OGRLayer::Union().

Parameters:
pLayerInput the input layer. Should not be NULL.
pLayerMethod the method layer. Should not be NULL.
pLayerResult the layer where the features resulting from the operation are inserted. Should not be NULL. See above the note about the schema.
papszOptions NULL terminated list of options (may be NULL).
pfnProgress a GDALProgressFunc() compatible callback function for reporting progress or NULL.
pProgressArg argument to be passed to pfnProgress. May be NULL.
Returns:
an error code if there was an error or the execution was interrupted, OGRERR_NONE otherwise.
Since:
OGR 1.10
OGRErr OGR_L_Update ( OGRLayerH  pLayerInput,
OGRLayerH  pLayerMethod,
OGRLayerH  pLayerResult,
char **  papszOptions,
GDALProgressFunc  pfnProgress,
void *  pProgressArg 
)

Update this layer with features from the update layer.

The result layer contains features whose geometries represent areas that are either in the input layer or in the method layer. The features in the result layer have areas of the features of the method layer or those ares of the features of the input layer that are not covered by the method layer. The features of the result layer get their attributes from the input layer. The schema of the result layer can be set by the user or, if it is empty, is initialized to contain all fields in the input layer.

Note:
If the schema of the result is set by user and contains fields that have the same name as a field in the method layer, then the attribute in the result feature the originates from the method layer will get the value from the feature of the method layer.
For best performance use the minimum amount of features in the method layer and copy it into a memory layer.
This method relies on GEOS support. Do not use unless the GEOS support is compiled in.

The recognized list of options is :

  • SKIP_FAILURES=YES/NO. Set it to YES to go on, even when a feature could not be inserted.
  • PROMOTE_TO_MULTI=YES/NO. Set it to YES to convert Polygons into MultiPolygons, or LineStrings to MultiLineStrings.
  • INPUT_PREFIX=string. Set a prefix for the field names that will be created from the fields of the input layer.
  • METHOD_PREFIX=string. Set a prefix for the field names that will be created from the fields of the method layer.

This function is the same as the C++ method OGRLayer::Update().

Parameters:
pLayerInput the input layer. Should not be NULL.
pLayerMethod the method layer. Should not be NULL.
pLayerResult the layer where the features resulting from the operation are inserted. Should not be NULL. See above the note about the schema.
papszOptions NULL terminated list of options (may be NULL).
pfnProgress a GDALProgressFunc() compatible callback function for reporting progress or NULL.
pProgressArg argument to be passed to pfnProgress. May be NULL.
Returns:
an error code if there was an error or the execution was interrupted, OGRERR_NONE otherwise.
Since:
OGR 1.10
int OGR_SM_AddPart ( OGRStyleMgrH  hSM,
OGRStyleToolH  hST 
)

Add a part (style tool) to the current style.

This function is the same as the C++ method OGRStyleMgr::AddPart().

Parameters:
hSM handle to the style manager.
hST the style tool defining the part to add.
Returns:
TRUE on success, FALSE on errors.
int OGR_SM_AddStyle ( OGRStyleMgrH  hSM,
const char *  pszStyleName,
const char *  pszStyleString 
)

Add a style to the current style table.

This function is the same as the C++ method OGRStyleMgr::AddStyle().

Parameters:
hSM handle to the style manager.
pszStyleName the name of the style to add.
pszStyleString the style string to use, or NULL to use the style stored in the manager.
Returns:
TRUE on success, FALSE on errors.
OGRStyleMgrH OGR_SM_Create ( OGRStyleTableH  hStyleTable  ) 

OGRStyleMgr factory.

This function is the same as the C++ method OGRStyleMgr::OGRStyleMgr().

Parameters:
hStyleTable pointer to OGRStyleTable or NULL if not working with a style table.
Returns:
an handle to the new style manager object.
void OGR_SM_Destroy ( OGRStyleMgrH  hSM  ) 

Destroy Style Manager.

This function is the same as the C++ method OGRStyleMgr::~OGRStyleMgr().

Parameters:
hSM handle to the style manager to destroy.
OGRStyleToolH OGR_SM_GetPart ( OGRStyleMgrH  hSM,
int  nPartId,
const char *  pszStyleString 
)

Fetch a part (style tool) from the current style.

This function is the same as the C++ method OGRStyleMgr::GetPart().

This function instanciates a new object that should be freed with OGR_ST_Destroy().

Parameters:
hSM handle to the style manager.
nPartId the part number (0-based index).
pszStyleString (optional) the style string on which to operate. If NULL then the current style string stored in the style manager is used.
Returns:
OGRStyleToolH of the requested part (style tools) or NULL on error.
int OGR_SM_GetPartCount ( OGRStyleMgrH  hSM,
const char *  pszStyleString 
)

Get the number of parts in a style.

This function is the same as the C++ method OGRStyleMgr::GetPartCount().

Parameters:
hSM handle to the style manager.
pszStyleString (optional) the style string on which to operate. If NULL then the current style string stored in the style manager is used.
Returns:
the number of parts (style tools) in the style.
const char* OGR_SM_InitFromFeature ( OGRStyleMgrH  hSM,
OGRFeatureH  hFeat 
)

Initialize style manager from the style string of a feature.

This function is the same as the C++ method OGRStyleMgr::InitFromFeature().

Parameters:
hSM handle to the style manager.
hFeat handle to the new feature from which to read the style.
Returns:
a reference to the style string read from the feature, or NULL in case of error.
int OGR_SM_InitStyleString ( OGRStyleMgrH  hSM,
const char *  pszStyleString 
)

Initialize style manager from the style string.

This function is the same as the C++ method OGRStyleMgr::InitStyleString().

Parameters:
hSM handle to the style manager.
pszStyleString the style string to use (can be NULL).
Returns:
TRUE on success, FALSE on errors.
OGRStyleToolH OGR_ST_Create ( OGRSTClassId  eClassId  ) 

OGRStyleTool factory.

This function is a constructor for OGRStyleTool derived classes.

Parameters:
eClassId subclass of style tool to create. One of OGRSTCPen (1), OGRSTCBrush (2), OGRSTCSymbol (3) or OGRSTCLabel (4).
Returns:
an handle to the new style tool object or NULL if the creation failed.
void OGR_ST_Destroy ( OGRStyleToolH  hST  ) 

Destroy Style Tool.

Parameters:
hST handle to the style tool to destroy.
double OGR_ST_GetParamDbl ( OGRStyleToolH  hST,
int  eParam,
int *  bValueIsNull 
)

Get Style Tool parameter value as a double.

Maps to the OGRStyleTool subclasses' GetParamDbl() methods.

Parameters:
hST handle to the style tool.
eParam the parameter id from the enumeration corresponding to the type of this style tool (one of the OGRSTPenParam, OGRSTBrushParam, OGRSTSymbolParam or OGRSTLabelParam enumerations)
bValueIsNull pointer to an integer that will be set to TRUE or FALSE to indicate whether the parameter value is NULL.
Returns:
the parameter value as double and sets bValueIsNull.
int OGR_ST_GetParamNum ( OGRStyleToolH  hST,
int  eParam,
int *  bValueIsNull 
)

Get Style Tool parameter value as an integer.

Maps to the OGRStyleTool subclasses' GetParamNum() methods.

Parameters:
hST handle to the style tool.
eParam the parameter id from the enumeration corresponding to the type of this style tool (one of the OGRSTPenParam, OGRSTBrushParam, OGRSTSymbolParam or OGRSTLabelParam enumerations)
bValueIsNull pointer to an integer that will be set to TRUE or FALSE to indicate whether the parameter value is NULL.
Returns:
the parameter value as integer and sets bValueIsNull.
const char* OGR_ST_GetParamStr ( OGRStyleToolH  hST,
int  eParam,
int *  bValueIsNull 
)

Get Style Tool parameter value as string.

Maps to the OGRStyleTool subclasses' GetParamStr() methods.

Parameters:
hST handle to the style tool.
eParam the parameter id from the enumeration corresponding to the type of this style tool (one of the OGRSTPenParam, OGRSTBrushParam, OGRSTSymbolParam or OGRSTLabelParam enumerations)
bValueIsNull pointer to an integer that will be set to TRUE or FALSE to indicate whether the parameter value is NULL.
Returns:
the parameter value as string and sets bValueIsNull.
int OGR_ST_GetRGBFromString ( OGRStyleToolH  hST,
const char *  pszColor,
int *  pnRed,
int *  pnGreen,
int *  pnBlue,
int *  pnAlpha 
)

Return the r,g,b,a components of a color encoded in #RRGGBB[AA] format.

Maps to OGRStyleTool::GetRGBFromString().

Parameters:
hST handle to the style tool.
pszColor the color to parse
pnRed pointer to an int in which the red value will be returned
pnGreen pointer to an int in which the green value will be returned
pnBlue pointer to an int in which the blue value will be returned
pnAlpha pointer to an int in which the (optional) alpha value will be returned
Returns:
TRUE if the color could be succesfully parsed, or FALSE in case of errors.
const char* OGR_ST_GetStyleString ( OGRStyleToolH  hST  ) 

Get the style string for this Style Tool.

Maps to the OGRStyleTool subclasses' GetStyleString() methods.

Parameters:
hST handle to the style tool.
Returns:
the style string for this style tool or "" if the hST is invalid.
OGRSTClassId OGR_ST_GetType ( OGRStyleToolH  hST  ) 

Determine type of Style Tool.

Parameters:
hST handle to the style tool.
Returns:
the style tool type, one of OGRSTCPen (1), OGRSTCBrush (2), OGRSTCSymbol (3) or OGRSTCLabel (4). Returns OGRSTCNone (0) if the OGRStyleToolH is invalid.
OGRSTUnitId OGR_ST_GetUnit ( OGRStyleToolH  hST  ) 

Get Style Tool units.

Parameters:
hST handle to the style tool.
Returns:
the style tool units.
void OGR_ST_SetParamDbl ( OGRStyleToolH  hST,
int  eParam,
double  dfValue 
)

Set Style Tool parameter value from a double.

Maps to the OGRStyleTool subclasses' SetParamDbl() methods.

Parameters:
hST handle to the style tool.
eParam the parameter id from the enumeration corresponding to the type of this style tool (one of the OGRSTPenParam, OGRSTBrushParam, OGRSTSymbolParam or OGRSTLabelParam enumerations)
dfValue the new parameter value
void OGR_ST_SetParamNum ( OGRStyleToolH  hST,
int  eParam,
int  nValue 
)

Set Style Tool parameter value from an integer.

Maps to the OGRStyleTool subclasses' SetParamNum() methods.

Parameters:
hST handle to the style tool.
eParam the parameter id from the enumeration corresponding to the type of this style tool (one of the OGRSTPenParam, OGRSTBrushParam, OGRSTSymbolParam or OGRSTLabelParam enumerations)
nValue the new parameter value
void OGR_ST_SetParamStr ( OGRStyleToolH  hST,
int  eParam,
const char *  pszValue 
)

Set Style Tool parameter value from a string.

Maps to the OGRStyleTool subclasses' SetParamStr() methods.

Parameters:
hST handle to the style tool.
eParam the parameter id from the enumeration corresponding to the type of this style tool (one of the OGRSTPenParam, OGRSTBrushParam, OGRSTSymbolParam or OGRSTLabelParam enumerations)
pszValue the new parameter value
void OGR_ST_SetUnit ( OGRStyleToolH  hST,
OGRSTUnitId  eUnit,
double  dfGroundPaperScale 
)

Set Style Tool units.

This function is the same as OGRStyleTool::SetUnit()

Parameters:
hST handle to the style tool.
eUnit the new unit.
dfGroundPaperScale ground to paper scale factor.
int OGR_STBL_AddStyle ( OGRStyleTableH  hStyleTable,
const char *  pszName,
const char *  pszStyleString 
)

Add a new style in the table.

No comparison will be done on the Style string, only on the name. This function is the same as the C++ method OGRStyleTable::AddStyle().

Parameters:
hStyleTable handle to the style table.
pszName the name the style to add.
pszStyleString the style string to add.
Returns:
TRUE on success, FALSE on error
OGRStyleTableH OGR_STBL_Create ( void   ) 

OGRStyleTable factory.

This function is the same as the C++ method OGRStyleTable::OGRStyleTable().

Returns:
an handle to the new style table object.
void OGR_STBL_Destroy ( OGRStyleTableH  hSTBL  ) 

Destroy Style Table.

Parameters:
hSTBL handle to the style table to destroy.
const char* OGR_STBL_Find ( OGRStyleTableH  hStyleTable,
const char *  pszName 
)

Get a style string by name.

This function is the same as the C++ method OGRStyleTable::Find().

Parameters:
hStyleTable handle to the style table.
pszName the name of the style string to find.
Returns:
the style string matching the name or NULL if not found or error.
const char* OGR_STBL_GetLastStyleName ( OGRStyleTableH  hStyleTable  ) 

Get the style name of the last style string fetched with OGR_STBL_GetNextStyle.

This function is the same as the C++ method OGRStyleTable::GetStyleName().

Parameters:
hStyleTable handle to the style table.
Returns:
the Name of the last style string or NULL on error.
const char* OGR_STBL_GetNextStyle ( OGRStyleTableH  hStyleTable  ) 

Get the next style string from the table.

This function is the same as the C++ method OGRStyleTable::GetNextStyle().

Parameters:
hStyleTable handle to the style table.
Returns:
the next style string or NULL on error.
int OGR_STBL_LoadStyleTable ( OGRStyleTableH  hStyleTable,
const char *  pszFilename 
)

Load a style table from a file.

This function is the same as the C++ method OGRStyleTable::LoadStyleTable().

Parameters:
hStyleTable handle to the style table.
pszFilename the name of the file to load from.
Returns:
TRUE on success, FALSE on error
void OGR_STBL_ResetStyleStringReading ( OGRStyleTableH  hStyleTable  ) 

Reset the next style pointer to 0.

This function is the same as the C++ method OGRStyleTable::ResetStyleStringReading().

Parameters:
hStyleTable handle to the style table.
int OGR_STBL_SaveStyleTable ( OGRStyleTableH  hStyleTable,
const char *  pszFilename 
)

Save a style table to a file.

This function is the same as the C++ method OGRStyleTable::SaveStyleTable().

Parameters:
hStyleTable handle to the style table.
pszFilename the name of the file to save to.
Returns:
TRUE on success, FALSE on error
OGRGeometryH OGRBuildPolygonFromEdges ( OGRGeometryH  hLines,
int  bBestEffort,
int  bAutoClose,
double  dfTolerance,
OGRErr *  peErr 
)

Build a ring from a bunch of arcs.

Parameters:
hLines handle to an OGRGeometryCollection (or OGRMultiLineString) containing the line string geometries to be built into rings.
bBestEffort not yet implemented???.
bAutoClose indicates if the ring should be close when first and last points of the ring are the same.
dfTolerance tolerance into which two arcs are considered close enough to be joined.
peErr OGRERR_NONE on success, or OGRERR_FAILURE on failure.
Returns:
an handle to the new geometry, a polygon.
void OGRCleanupAll ( void   ) 

Cleanup all OGR related resources.

FIXME

OGRSFDriverH OGRGetDriver ( int  iDriver  ) 

Fetch the indicated driver.

Deprecated:
Use GDALGetDriver() in GDAL 2.0
Parameters:
iDriver the driver index, from 0 to GetDriverCount()-1.
Returns:
handle to the driver, or NULL if iDriver is out of range.
OGRSFDriverH OGRGetDriverByName ( const char *  pszName  ) 

Fetch the indicated driver.

Deprecated:
Use GDALGetDriverByName() in GDAL 2.0
Parameters:
pszName the driver name
Returns:
the driver, or NULL if no driver with that name is found
int OGRGetDriverCount ( void   ) 

Fetch the number of registered drivers.

Deprecated:
Use GDALGetDriverCount() in GDAL 2.0
Returns:
the drivers count.
int OGRGetNonLinearGeometriesEnabledFlag ( void   ) 

Get flag to enable/disable returning non-linear geometries in the C API.

return TRUE if non-linear geometries might be returned (default value is TRUE)

Since:
GDAL 2.0
See also:
OGRSetNonLinearGeometriesEnabledFlag()
OGRDataSourceH OGROpen ( const char *  pszName,
int  bUpdate,
OGRSFDriverH *  pahDriverList 
)

Open a file / data source with one of the registered drivers.

This function loops through all the drivers registered with the driver manager trying each until one succeeds with the given data source. This function is static. Applications don't normally need to use any other OGRSFDriverRegistrar function, not do they normally need to have a pointer to an OGRSFDriverRegistrar instance.

If this function fails, CPLGetLastErrorMsg() can be used to check if there is an error message explaining why.

For drivers supporting the VSI virtual file API, it is possible to open a file in a .zip archive (see VSIInstallZipFileHandler()), in a .tar/.tar.gz/.tgz archive (see VSIInstallTarFileHandler()) or on a HTTP / FTP server (see VSIInstallCurlFileHandler())

Deprecated:
Use GDALOpenEx() in GDAL 2.0
Parameters:
pszName the name of the file, or data source to open.
bUpdate FALSE for read-only access (the default) or TRUE for read-write access.
pahDriverList if non-NULL, this argument will be updated with a pointer to the driver which was used to open the data source.
Returns:
NULL on error or if the pass name is not supported by this driver, otherwise an handle to an OGRDataSource. This OGRDataSource should be closed by deleting the object when it is no longer needed.

Example:

    OGRDataSourceH	hDS;
    OGRSFDriverH        *pahDriver;
    hDS = OGROpen( "polygon.shp", 0, pahDriver );
    if( hDS == NULL )
    {
        return;
    }
    ... use the data source ...
    OGRReleaseDataSource( hDS );
  
int OGRRegisterAll ( void   ) 

Register all drivers.

Deprecated:
Use GDALAllRegister() in GDAL 2.0
OGRErr OGRReleaseDataSource ( OGRDataSourceH  hDS  ) 

Drop a reference to this datasource, and if the reference count drops to zero close (destroy) the datasource.

Internally this actually calls the OGRSFDriverRegistrar::ReleaseDataSource() method. This method is essentially a convenient alias.

Deprecated:
Use GDALClose() in GDAL 2.0
Parameters:
hDS handle to the data source to release
Returns:
OGRERR_NONE on success or an error code.
OGRErr OGRSetGenerate_DB2_V72_BYTE_ORDER ( int  bGenerate_DB2_V72_BYTE_ORDER  ) 

Special entry point to enable the hack for generating DB2 V7.2 style WKB.

DB2 seems to have placed (and require) an extra 0x30 or'ed with the byte order in WKB. This entry point is used to turn on or off the generation of such WKB.

void OGRSetNonLinearGeometriesEnabledFlag ( int  bFlag  ) 

Set flag to enable/disable returning non-linear geometries in the C API.

This flag has only an effect on the OGR_F_GetGeometryRef(), OGR_F_GetGeomFieldRef(), OGR_L_GetGeomType(), OGR_GFld_GetType() and OGR_FD_GetGeomType() C API, and corresponding methods in the SWIG bindings. It is meant as making it simple for applications using the OGR C API not to have to deal with non-linear geometries, even if such geometries might be returned by drivers. In which case, they will be transformed into their closest linear geometry, by doing linear approximation, with OGR_G_ForceTo().

Libraries should generally *not* use that method, since that could interfere with other libraries or applications.

Note that it *does* not affect the behaviour of the C++ API.

Parameters:
bFlag TRUE if non-linear geometries might be returned (default value). FALSE to ask for non-linear geometries to be approximated as linear geometries.
Returns:
a point or NULL.
Since:
GDAL 2.0

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