[gdal-dev] Open source vector geoprocessing libraries?

[Frank Warmerdam]

Jan Hartmann wrote:
> Is that so? Reading the OGR API tutorial 
> (http://www.gdal.org/ogr/ogr_apitut.html), I see that all geometries, 
> frowm whatever input source, are represented internally as a generic 
> OGRGeometry pointer, which is a virtual base class for all real geometry 
> classes (http://www.gdal.org/ogr/classOGRGeometry.html). Most of the 
> GEOS functionality can be implemented on OGRGeometries, so in principle 
> the same could be done with indexing libraries (GIST, b-tree, quadtree, 
> etc). Such indices should be written out to disk to be of any use at 
> all, of course, like shptree does.

Jan,

I have had trouble keeping up with this spirited discussion, but I wanted
to note that it is not intended that alternate implementations of geometries
would be derived by OGRGeometry.  There are many places for instance that
assume an OGRGeometry can be cast to OGRLineString if it's type is
wkbLineString.

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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and watch the world go round - Rush    | Geospatial Programmer for Rent