[Gdal-dev] Problems with PostGIS and Shapefile interface

[rompenb at unbc.ca]

Hi, I've been having major difficulties in programming with the OGR API.  
Currently I'm attempting to write a program that reads features from a
PostGIS database and writes them to an ESRI Shapefile.   The following
strange problems are occurring:

1) When I read a feature from the PostGIS database, both of the following
statements
   currentfeat->GetGeometryRef()->getGeometryType()
   loadlayer->GetLayerDefn()->GetGeomType()
return 0, or 'wkbUnknown', when according to currentfeat->DumpReadable()
all the features in the database table are multipolygons.

2)OGRGeometryFactory::forceToPolygon() isn't working.   According to the
following code,
   currentfeat->DumpReadable(dumpfile);
   destfeat->SetGeometryDirectly(
            OGRGeometryFactory::forceToPolygon(destfeat->StealGeometry()));
   destfeat->DumpReadable(dumpfile);
the geometry remains in multipolygon format.   destfeat previously had its
geometry created via OGRFeature::SetFrom().

3)When I re-read the shapefile following translation, using
OGRFeature::DumpReadable() again, the features appear as a mixture of
polygons and multipolygons.

If anyone has any suggestions, they would be greatly appreciated.

Thank you for your time.

Ben