builds vector contour lines from a raster elevation model
Usage: gdal_contour [-b <band>] [-a <attribute_name>] [-3d] [-inodata] [-snodata n] [-i <interval>] [-f <formatname>] [[-dsco NAME=VALUE] ...] [[-lco NAME=VALUE] ...] [-off <offset>] [-fl <level> <level>...] [-nln <outlayername>] <src_filename> <dst_filename>
This program generates a vector contour file from the input raster elevation model (DEM).
Starting from version 1.7 the contour line-strings will be oriented consistently. The high side will be on the right, i.e. a line string goes clockwise around a top.
picks a particular band to get the DEM from. Defaults to band 1.
Force production of 3D vectors instead of 2D. Includes elevation at every vertex.
Ignore any nodata value implied in the dataset - treat all values as valid.
Input pixel value to treat as "nodata".
create output in a particular format, default is shapefiles.
Layer creation option (format specific)
elevation interval between contours.
Offset from zero relative to which to interpret intervals.
This would create 10meter contours from the DEM data in dem.tif and produce a shapefile in contour.shp/shx/dbf with the contour elevations in the "elev" attribute.
gdal_contour -a elev dem.tif contour.shp -i 10.0