GDAL

Abstract base class for all geometry classes. More...
#include <ogr_geometry.h>
Public Member Functions  
OGRGeometry (const OGRGeometry &other)  
Copy constructor. More...  
OGRGeometry &  operator= (const OGRGeometry &other) 
Assignment operator. More...  
virtual int  getDimension () const =0 
Get the dimension of this object. More...  
virtual int  getCoordinateDimension () const 
Get the dimension of the coordinates in this object. More...  
int  CoordinateDimension () const 
Get the dimension of the coordinates in this object. More...  
virtual OGRBoolean  IsEmpty () const 
Returns TRUE (nonzero) if the object has no points. More...  
virtual OGRBoolean  IsValid () const 
Test if the geometry is valid. More...  
virtual OGRBoolean  IsSimple () const 
Test if the geometry is simple. More...  
OGRBoolean  Is3D () const 
OGRBoolean  IsMeasured () const 
virtual OGRBoolean  IsRing () const 
Test if the geometry is a ring. More...  
virtual void  empty ()=0 
Clear geometry information. More...  
virtual OGRGeometry *  clone () const CPL_WARN_UNUSED_RESULT=0 
Make a copy of this object. More...  
virtual void  getEnvelope (OGREnvelope *psEnvelope) const =0 
Computes and returns the bounding envelope for this geometry in the passed psEnvelope structure. More...  
virtual void  getEnvelope (OGREnvelope3D *psEnvelope) const =0 
Computes and returns the bounding envelope (3D) for this geometry in the passed psEnvelope structure. More...  
virtual int  WkbSize () const =0 
Returns size of related binary representation. More...  
virtual OGRErr  importFromWkb (unsigned char *, int=1, OGRwkbVariant=wkbVariantOldOgc)=0 
Assign geometry from well known binary data. More...  
virtual OGRErr  exportToWkb (OGRwkbByteOrder, unsigned char *, OGRwkbVariant=wkbVariantOldOgc) const =0 
Convert a geometry into well known binary format. More...  
virtual OGRErr  importFromWkt (char **ppszInput)=0 
Assign geometry from well known text data. More...  
virtual OGRErr  exportToWkt (char **ppszDstText, OGRwkbVariant=wkbVariantOldOgc) const =0 
Convert a geometry into well known text format. More...  
virtual OGRwkbGeometryType  getGeometryType () const =0 
Fetch geometry type. More...  
OGRwkbGeometryType  getIsoGeometryType () const 
Get the geometry type that conforms with ISO SQL/MM Part3. More...  
virtual const char *  getGeometryName () const =0 
Fetch WKT name for geometry type. More...  
virtual void  dumpReadable (FILE *, const char *=NULL, char **papszOptions=NULL) const 
Dump geometry in well known text format to indicated output file. More...  
virtual void  flattenTo2D ()=0 
Convert geometry to strictly 2D. More...  
virtual char *  exportToGML (const char *const *papszOptions=NULL) const 
Convert a geometry into GML format. More...  
virtual char *  exportToKML () const 
Convert a geometry into KML format. More...  
virtual char *  exportToJson () const 
Convert a geometry into GeoJSON format. More...  
virtual GEOSGeom  exportToGEOS (GEOSContextHandle_t hGEOSCtxt) const CPL_WARN_UNUSED_RESULT 
Returns a GEOSGeom object corresponding to the geometry. More...  
virtual OGRBoolean  hasCurveGeometry (int bLookForNonLinear=FALSE) const 
Returns if this geometry is or has curve geometry. More...  
virtual OGRGeometry *  getCurveGeometry (const char *const *papszOptions=NULL) const CPL_WARN_UNUSED_RESULT 
Return curve version of this geometry. More...  
virtual OGRGeometry *  getLinearGeometry (double dfMaxAngleStepSizeDegrees=0, const char *const *papszOptions=NULL) const CPL_WARN_UNUSED_RESULT 
Return, possibly approximate, noncurve version of this geometry. More...  
virtual void  closeRings () 
Force rings to be closed. More...  
virtual void  setCoordinateDimension (int nDimension) 
Set the coordinate dimension. More...  
virtual void  set3D (OGRBoolean bIs3D) 
Add or remove the Z coordinate dimension. More...  
virtual void  setMeasured (OGRBoolean bIsMeasured) 
Add or remove the M coordinate dimension. More...  
void  assignSpatialReference (OGRSpatialReference *poSR) 
Assign spatial reference to this object. More...  
OGRSpatialReference *  getSpatialReference (void) const 
Returns spatial reference system for object. More...  
virtual OGRErr  transform (OGRCoordinateTransformation *poCT)=0 
Apply arbitrary coordinate transformation to geometry. More...  
OGRErr  transformTo (OGRSpatialReference *poSR) 
Transform geometry to new spatial reference system. More...  
virtual void  segmentize (double dfMaxLength) 
Modify the geometry such it has no segment longer then the given distance. More...  
virtual OGRBoolean  Intersects (const OGRGeometry *) const 
Do these features intersect? More...  
virtual OGRBoolean  Equals (OGRGeometry *) const =0 
Returns TRUE if two geometries are equivalent. More...  
virtual OGRBoolean  Disjoint (const OGRGeometry *) const 
Test for disjointness. More...  
virtual OGRBoolean  Touches (const OGRGeometry *) const 
Test for touching. More...  
virtual OGRBoolean  Crosses (const OGRGeometry *) const 
Test for crossing. More...  
virtual OGRBoolean  Within (const OGRGeometry *) const 
Test for containment. More...  
virtual OGRBoolean  Contains (const OGRGeometry *) const 
Test for containment. More...  
virtual OGRBoolean  Overlaps (const OGRGeometry *) const 
Test for overlap. More...  
virtual OGRGeometry *  Boundary () const CPL_WARN_UNUSED_RESULT 
Compute boundary. More...  
virtual double  Distance (const OGRGeometry *) const 
Compute distance between two geometries. More...  
virtual OGRGeometry *  ConvexHull () const CPL_WARN_UNUSED_RESULT 
Compute convex hull. More...  
virtual OGRGeometry *  Buffer (double dfDist, int nQuadSegs=30) const CPL_WARN_UNUSED_RESULT 
Compute buffer of geometry. More...  
virtual OGRGeometry *  Intersection (const OGRGeometry *) const CPL_WARN_UNUSED_RESULT 
Compute intersection. More...  
virtual OGRGeometry *  Union (const OGRGeometry *) const CPL_WARN_UNUSED_RESULT 
Compute union. More...  
virtual OGRGeometry *  UnionCascaded () const CPL_WARN_UNUSED_RESULT 
Compute union using cascading. More...  
virtual OGRGeometry *  Difference (const OGRGeometry *) const CPL_WARN_UNUSED_RESULT 
Compute difference. More...  
virtual OGRGeometry *  SymDifference (const OGRGeometry *) const CPL_WARN_UNUSED_RESULT 
Compute symmetric difference. More...  
virtual OGRErr  Centroid (OGRPoint *poPoint) const 
Compute the geometry centroid. More...  
virtual OGRGeometry *  Simplify (double dTolerance) const CPL_WARN_UNUSED_RESULT 
Simplify the geometry. More...  
OGRGeometry *  SimplifyPreserveTopology (double dTolerance) const CPL_WARN_UNUSED_RESULT 
Simplify the geometry while preserving topology. More...  
virtual OGRGeometry *  DelaunayTriangulation (double dfTolerance, int bOnlyEdges) const CPL_WARN_UNUSED_RESULT 
Return a Delaunay triangulation of the vertices of the geometry. More...  
virtual OGRGeometry *  Polygonize () const CPL_WARN_UNUSED_RESULT 
Polygonizes a set of sparse edges. More...  
virtual void  swapXY () 
Swap x and y coordinates. More...  
Static Public Member Functions  
static GEOSContextHandle_t  createGEOSContext () 
Create a new GEOS context. More...  
static void  freeGEOSContext (GEOSContextHandle_t hGEOSCtxt) 
Destroy a GEOS context. More...  
Abstract base class for all geometry classes.
Some spatial analysis methods require that OGR is built on the GEOS library to work properly. The precise meaning of methods that describe spatial relationships between geometries is described in the SFCOM, or other simple features interface specifications, like "OpenGISĀ® Implementation Specification for Geographic information  Simple feature access  Part 1: Common architecture" (OGC 06103r4)
In GDAL 2.0, the hierarchy of classes has been extended with (working draft) ISO SQL/MM Part 3 (ISO/IEC 132493) curve geometries : CIRCULARSTRING (OGRCircularString), COMPOUNDCURVE (OGRCompoundCurve), CURVEPOLYGON (OGRCurvePolygon), MULTICURVE (OGRMultiCurve) and MULTISURFACE (OGRMultiSurface).
OGRGeometry::OGRGeometry  (  const OGRGeometry &  other  ) 
Copy constructor.
Note: before GDAL 2.1, only the default implementation of the constructor existed, which could be unsafe to use.
void OGRGeometry::assignSpatialReference  (  OGRSpatialReference *  poSR  ) 
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 method is the same as the C function OGR_G_AssignSpatialReference().
poSR  new spatial reference system to apply. 

virtual 
Compute boundary.
A new geometry object is created and returned containing the boundary of the geometry on which the method is invoked.
This method is the same as the C function OGR_G_Boundary().
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.

virtual 
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 segments 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 method is the same as the C function OGR_G_Buffer().
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.
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. 
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/MMPart 3 defines the operation for surfaces and multisurfaces (multipolygons).
This function is the same as the C function OGR_G_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.

pure virtual 
Make a copy of this object.
This method relates to the SFCOM IGeometry::clone() method.
This method is the same as the C function OGR_G_Clone().
Implemented in OGRGeometryCollection, OGRCurvePolygon, OGRCompoundCurve, OGRLinearRing, OGRSimpleCurve, and OGRPoint.

virtual 
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.
Reimplemented in OGRGeometryCollection, OGRPolygon, and OGRLinearRing.

virtual 
Test for containment.
Tests if actual geometry object contains the passed geometry.
This method is the same as the C function OGR_G_Contains().
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.
poOtherGeom  the geometry to compare to this geometry. 
Reimplemented in OGRCurvePolygon.

virtual 
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 method is the same as the C function OGR_G_ConvexHull().
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.
int OGRGeometry::CoordinateDimension  (  )  const 
Get the dimension of the coordinates in this object.
This method is the same as the C function OGR_G_CoordinateDimension().

static 
Create a new GEOS context.

virtual 
Test for crossing.
Tests if this geometry and the other passed into the method are crossing.
This method is the same as the C function OGR_G_Crosses().
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.
poOtherGeom  the geometry to compare to this geometry. 

virtual 
Return a Delaunay triangulation of the vertices of the geometry.
This function is the same as the C function OGR_G_DelaunayTriangulation().
This function is built on the GEOS library, v3.4 or above. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.
dfTolerance  optional snapping tolerance to use for improved robustness 
bOnlyEdges  if TRUE, will return a MULTILINESTRING, otherwise it will return a GEOMETRYCOLLECTION containing triangular POLYGONs. 

virtual 
Compute difference.
Generates a new geometry which is the region of this geometry with the region of the second geometry removed.
This method is the same as the C function OGR_G_Difference().
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.
poOtherGeom  the other geometry removed from "this" geometry. 

virtual 
Test for disjointness.
Tests if this geometry and the other passed into the method are disjoint.
This method is the same as the C function OGR_G_Disjoint().
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.
poOtherGeom  the geometry to compare to this geometry. 

virtual 
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 method is the same as the C function OGR_G_Distance().
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.
poOtherGeom  the other geometry to compare against. 

virtual 
Dump geometry in well known text format to indicated output file.
A few options can be defined to change the default dump :
This method is the same as the C function OGR_G_DumpReadable().
fp  the text file to write the geometry to. 
pszPrefix  the prefix to put on each line of output. 
papszOptions  NULL terminated list of options (may be NULL) 

pure virtual 
Clear geometry information.
This restores the geometry to it's initial state after construction, and before assignment of actual geometry.
This method relates to the SFCOM IGeometry::Empty() method.
This method is the same as the C function OGR_G_Empty().
Implemented in OGRGeometryCollection, OGRCurvePolygon, OGRCompoundCurve, OGRSimpleCurve, and OGRPoint.

pure virtual 
Returns TRUE if two geometries are equivalent.
This method is the same as the C function OGR_G_Equals().
Implemented in OGRGeometryCollection, OGRCurvePolygon, OGRCompoundCurve, OGRSimpleCurve, and OGRPoint.

virtual 
Returns a GEOSGeom object corresponding to the geometry.
hGEOSCtxt  GEOS context 

virtual 
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 in OGR 1.8.0 are :
This method is the same as the C function OGR_G_ExportToGMLEx().
papszOptions  NULLterminated list of options. 

virtual 
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 function OGR_G_ExportToJson().

virtual 
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 function OGR_G_ExportToKML().

pure virtual 
Convert a geometry into well known binary format.
This method relates to the SFCOM IWks::ExportToWKB() method.
This method is the same as the C function OGR_G_ExportToWkb() or OGR_G_ExportToIsoWkb(), depending on the value of eWkbVariant.
eByteOrder  One of wkbXDR or wkbNDR indicating MSB or LSB byte order respectively. 
pabyData  a buffer into which the binary representation is written. This buffer must be at least OGRGeometry::WkbSize() byte in size. 
eWkbVariant  What standard to use when exporting geometries with three dimensions (or more). The default wkbVariantOldOgc is the historical OGR variant. wkbVariantIso is the variant defined in ISO SQL/MM and adopted by OGC for SFSQL 1.2. 
Implemented in OGRGeometryCollection, OGRPolygon, OGRCurvePolygon, OGRCompoundCurve, OGRCircularString, OGRLinearRing, OGRSimpleCurve, and OGRPoint.

pure virtual 
Convert a geometry into well known text format.
This method relates to the SFCOM IWks::ExportToWKT() method.
This method is the same as the C function OGR_G_ExportToWkt().
ppszDstText  a text buffer is allocated by the program, and assigned to the passed pointer. After use, *ppszDstText should be freed with OGRFree(). 
eWkbVariant  the specification that must be conformed too :

Implemented in OGRMultiLineString, OGRMultiCurve, OGRMultiPoint, OGRMultiPolygon, OGRMultiSurface, OGRGeometryCollection, OGRPolygon, OGRCurvePolygon, OGRCompoundCurve, OGRCircularString, OGRSimpleCurve, and OGRPoint.

pure virtual 
Convert geometry to strictly 2D.
In a sense this converts all Z coordinates to 0.0.
This method is the same as the C function OGR_G_FlattenTo2D().
Implemented in OGRGeometryCollection, OGRCurvePolygon, OGRCompoundCurve, OGRSimpleCurve, and OGRPoint.

static 
Destroy a GEOS context.
hGEOSCtxt  GEOS context 

virtual 
Get the dimension of the coordinates in this object.
This method is the same as the C function OGR_G_GetCoordinateDimension().

virtual 
Return curve version of this geometry.
Returns a geometry that has possibly CIRCULARSTRING, COMPOUNDCURVE, CURVEPOLYGON, MULTICURVE or MULTISURFACE in it, by deapproximating 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 method is OGRGeometry::getLinearGeometry().
This function is the same as C function OGR_G_GetCurveGeometry().
papszOptions  options as a nullterminated list of strings. Unused for now. Must be set to NULL. 
Reimplemented in OGRGeometryCollection, OGRPolygon, and OGRLineString.

pure virtual 
Get the dimension of this object.
This method corresponds to the SFCOM IGeometry::GetDimension() method. It indicates the dimension of the object, but does not indicate the dimension of the underlying space (as indicated by OGRGeometry::getCoordinateDimension()).
This method is the same as the C function OGR_G_GetDimension().
Implemented in OGRMultiCurve, OGRMultiPoint, OGRMultiSurface, OGRGeometryCollection, OGRCurvePolygon, OGRCurve, and OGRPoint.

pure virtual 
Computes and returns the bounding envelope for this geometry in the passed psEnvelope structure.
This method is the same as the C function OGR_G_GetEnvelope().
psEnvelope  the structure in which to place the results. 
Implemented in OGRGeometryCollection, OGRCurvePolygon, OGRCompoundCurve, OGRCircularString, OGRSimpleCurve, and OGRPoint.

pure virtual 
Computes and returns the bounding envelope (3D) for this geometry in the passed psEnvelope structure.
This method is the same as the C function OGR_G_GetEnvelope3D().
psEnvelope  the structure in which to place the results. 
Implemented in OGRGeometryCollection, OGRCurvePolygon, OGRCompoundCurve, OGRCircularString, OGRSimpleCurve, and OGRPoint.

pure virtual 
Fetch WKT name for geometry type.
There is no SFCOM analog to this method.
This method is the same as the C function OGR_G_GetGeometryName().
Implemented in OGRMultiLineString, OGRMultiCurve, OGRMultiPoint, OGRMultiPolygon, OGRMultiSurface, OGRGeometryCollection, OGRPolygon, OGRCurvePolygon, OGRCompoundCurve, OGRCircularString, OGRLinearRing, OGRLineString, and OGRPoint.

pure virtual 
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 method is the same as the C function OGR_G_GetGeometryType().
Implemented in OGRMultiLineString, OGRMultiCurve, OGRMultiPoint, OGRMultiPolygon, OGRMultiSurface, OGRGeometryCollection, OGRPolygon, OGRCurvePolygon, OGRCompoundCurve, OGRCircularString, OGRLineString, and OGRPoint.
OGRwkbGeometryType OGRGeometry::getIsoGeometryType  (  )  const 
Get the geometry type that conforms with ISO SQL/MM Part3.

virtual 
Return, possibly approximate, noncurve 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 method is OGRGeometry::getCurveGeometry().
This method is the same as the C function OGR_G_GetLinearGeometry().
dfMaxAngleStepSizeDegrees  the largest step in degrees along the arc, zero to use the default setting. 
papszOptions  options as a nullterminated list of strings. See OGRGeometryFactory::curveToLineString() for valid options. 
Reimplemented in OGRGeometryCollection, OGRPolygon, OGRCurvePolygon, OGRCompoundCurve, and OGRCircularString.

inline 
Returns spatial reference system for object.
This method relates to the SFCOM IGeometry::get_SpatialReference() method.
This method is the same as the C function OGR_G_GetSpatialReference().

virtual 
Returns if this geometry is or has curve geometry.
Returns if a geometry is, contains or may contain a CIRCULARSTRING, COMPOUNDCURVE, CURVEPOLYGON, MULTICURVE or MULTISURFACE.
If bLookForNonLinear is set to TRUE, it will be actually looked if the geometry or its subgeometries are or contain a nonlinear geometry in them. In which case, if the method returns TRUE, it means that getLinearGeometry() would return an approximate version of the geometry. Otherwise, getLinearGeometry() would do a conversion, but with just converting container type, like COMPOUNDCURVE > LINESTRING, MULTICURVE > MULTILINESTRING or MULTISURFACE > MULTIPOLYGON, resulting in a "lossless" conversion.
This method is the same as the C function OGR_G_HasCurveGeometry().
bLookForNonLinear  set it to TRUE to check if the geometry is or contains a CIRCULARSTRING. 
Reimplemented in OGRMultiLineString, OGRMultiCurve, OGRMultiPoint, OGRMultiPolygon, OGRMultiSurface, OGRGeometryCollection, OGRPolygon, OGRCurvePolygon, OGRCompoundCurve, and OGRCircularString.

pure virtual 
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 method is used by the OGRGeometryFactory class, but not normally called by application code.
This method relates to the SFCOM IWks::ImportFromWKB() method.
This method is the same as the C function OGR_G_ImportFromWkb().
pabyData  the binary input data. 
nSize  the size of pabyData in bytes, or zero if not known. 
eWkbVariant  if wkbVariantPostGIS1, special interpretation is done for curve geometries code 
Implemented in OGRGeometryCollection, OGRPolygon, OGRCurvePolygon, OGRCompoundCurve, OGRCircularString, OGRLinearRing, OGRSimpleCurve, and OGRPoint.

pure virtual 
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 method is used by the OGRGeometryFactory class, but not normally called by application code.
This method relates to the SFCOM IWks::ImportFromWKT() method.
This method is the same as the C function OGR_G_ImportFromWkt().
ppszInput  pointer to a pointer to the source text. The pointer is updated to pointer after the consumed text. 
Implemented in OGRMultiCurve, OGRMultiPoint, OGRMultiSurface, OGRGeometryCollection, OGRPolygon, OGRCurvePolygon, OGRCompoundCurve, OGRCircularString, OGRSimpleCurve, and OGRPoint.

virtual 
Compute intersection.
Generates a new geometry which is the region of intersection of the two geometries operated on. The Intersects() method can be used to test if two geometries intersect.
This method is the same as the C function OGR_G_Intersection().
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.
poOtherGeom  the other geometry intersected with "this" geometry. 

virtual 
Do these features intersect?
Determines whether two geometries intersect. If GEOS is enabled, then this is done in rigorous fashion otherwise TRUE is returned if the envelopes (bounding boxes) of the two geometries overlap.
The poOtherGeom argument may be safely NULL, but in this case the method will always return TRUE. That is, a NULL geometry is treated as being everywhere.
This method is the same as the C function OGR_G_Intersects().
poOtherGeom  the other geometry to test against. 
Reimplemented in OGRCurvePolygon, and OGRPoint.

inline 
Returns whether the geometry has a Z component.

virtual 
Returns TRUE (nonzero) if the object has no points.
Normally this returns FALSE except between when an object is instantiated and points have been assigned.
This method relates to the SFCOM IGeometry::IsEmpty() method.
Reimplemented in OGRGeometryCollection, OGRCurvePolygon, OGRCompoundCurve, OGRSimpleCurve, and OGRPoint.

inline 
Returns whether the geometry has a M component.

virtual 
Test if the geometry is a ring.
This method is the same as the C function OGR_G_IsRing().
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 return FALSE.

virtual 
Test if the geometry is simple.
This method is the same as the C function OGR_G_IsSimple().
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 return FALSE.

virtual 
Test if the geometry is valid.
This method is the same as the C function OGR_G_IsValid().
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 return FALSE.
Reimplemented in OGRCircularString.
OGRGeometry & OGRGeometry::operator=  (  const OGRGeometry &  other  ) 
Assignment operator.
Note: before GDAL 2.1, only the default implementation of the operator existed, which could be unsafe to use.

virtual 
Test for overlap.
Tests if this geometry and the other passed into the method overlap, that is their intersection has a nonzero area.
This method is the same as the C function OGR_G_Overlaps().
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.
poOtherGeom  the geometry to compare to this geometry. 

virtual 
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 topological inconsistencies.
This method is the same as the C function OGR_G_Polygonize().
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.

virtual 
Modify the geometry such it has no segment longer then the given distance.
Add intermediate vertices to a geometry.
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 C function OGR_G_Segmentize()
dfMaxLength  the maximum distance between 2 points after segmentization 
This method modifies the geometry to add intermediate vertices if necessary so that the maximum length between 2 consecutive vertices is lower than dfMaxLength.
dfMaxLength  maximum length between 2 consecutive vertices. 
Reimplemented in OGRGeometryCollection, OGRCurvePolygon, OGRCompoundCurve, OGRCircularString, and OGRSimpleCurve.

virtual 
Add or remove the Z coordinate dimension.
This method adds or removes the explicit Z coordinate dimension. Removing the Z coordinate dimension of a geometry will remove any existing Z values. Adding the Z dimension to a geometry collection, a compound curve, a polygon, etc. will affect the children geometries.
bIs3D  Should the geometry have a Z dimension, either TRUE or FALSE. 
Reimplemented in OGRGeometryCollection, OGRCurvePolygon, OGRCompoundCurve, and OGRSimpleCurve.

virtual 
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, a compound curve, a polygon, etc. will affect the children geometries. This will also remove the M dimension if present before this call.
nNewDimension  New coordinate dimension value, either 2 or 3. 
Reimplemented in OGRGeometryCollection, OGRCurvePolygon, OGRCompoundCurve, OGRSimpleCurve, and OGRPoint.

virtual 
Add or remove the M coordinate dimension.
This method adds or removes the explicit M coordinate dimension. Removing the M coordinate dimension of a geometry will remove any existing M values. Adding the M dimension to a geometry collection, a compound curve, a polygon, etc. will affect the children geometries.
bIsMeasured  Should the geometry have a M dimension, either TRUE or FALSE. 
Reimplemented in OGRGeometryCollection, OGRCurvePolygon, OGRCompoundCurve, and OGRSimpleCurve.

virtual 
Simplify the geometry.
This function is the same as the C function OGR_G_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.
dTolerance  the distance tolerance for the simplification. 
OGRGeometry * OGRGeometry::SimplifyPreserveTopology  (  double  dTolerance  )  const 
Simplify the geometry while preserving topology.
This function is the same as the C function OGR_G_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.
dTolerance  the distance tolerance for the simplification. 

virtual 
Swap x and y coordinates.
Reimplemented in OGRGeometryCollection, OGRCurvePolygon, OGRCompoundCurve, OGRSimpleCurve, and OGRPoint.

virtual 
Compute symmetric difference.
Generates a new geometry which is the symmetric difference of this geometry and the second geometry passed into the method.
This method is the same as the C function OGR_G_SymDifference().
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.
poOtherGeom  the other geometry. 

virtual 
Test for touching.
Tests if this geometry and the other passed into the method are touching.
This method is the same as the C function OGR_G_Touches().
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.
poOtherGeom  the geometry to compare to this geometry. 

pure virtual 
Apply arbitrary coordinate transformation to geometry.
This method 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 method 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 method is the same as the C function OGR_G_Transform().
poCT  the transformation to apply. 
Implemented in OGRGeometryCollection, OGRCurvePolygon, OGRCompoundCurve, OGRSimpleCurve, and OGRPoint.
OGRErr OGRGeometry::transformTo  (  OGRSpatialReference *  poSR  ) 
Transform geometry to new spatial reference system.
This method 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 method 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 method requires internal creation and initialization of an OGRCoordinateTransformation object it is significantly more expensive to use this method to transform many geometries than it is to create the OGRCoordinateTransformation in advance, and call transform() with that transformation. This method exists primarily for convenience when only transforming a single geometry.
This method is the same as the C function OGR_G_TransformTo().
poSR  spatial reference system to transform to. 

virtual 
Compute union.
Generates a new geometry which is the region of union of the two geometries operated on.
This method is the same as the C function OGR_G_Union().
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.
poOtherGeom  the other geometry unioned with "this" geometry. 

virtual 
Compute union using cascading.
This method is the same as the C function OGR_G_UnionCascaded().
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.

virtual 
Test for containment.
Tests if actual geometry object is within the passed geometry.
This method is the same as the C function OGR_G_Within().
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.
poOtherGeom  the geometry to compare to this geometry. 
Reimplemented in OGRPoint.

pure virtual 
Returns size of related binary representation.
This method 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 method relates to the SFCOM IWks::WkbSize() method.
This method is the same as the C function OGR_G_WkbSize().
Implemented in OGRGeometryCollection, OGRPolygon, OGRCurvePolygon, OGRCompoundCurve, OGRLinearRing, OGRSimpleCurve, and OGRPoint.