Le jeudi 12 décembre 2013 23:39:25, Paul Ramsey a écrit : > I’ve been looking over the code, and I think I can make importFromWkb > consume ISO inputs with relatively minor changes. (during the geometry > type determination in the concrete types, it looks easy enough to add a > little logic to deal with ISO type numbers) For exportToWkb, I’m wondering > if maybe an optional parameter (wkbVariant?) that defaults to > wkbVariantOGC would be sufficient?
Sounds good to me. Is "wkbVariantOGC" the variant currently implemented ? Is our 3D support really compliant with an OGC standard ? > > It also seems the wkb reader/writer have little handling for empty geometry > types. I’d like to add some in, if that’s OK. Are you sure about that ? See : >>> from osgeo import ogr >>> ogr.CreateGeometryFromWkb(g.ExportToWkb()).ExportToWkt() 'LINESTRING EMPTY' >>> ogr.CreateGeometryFromWkb(ogr.CreateGeometryFromWkt('LINESTRING EMPTY').ExportToWkb()).ExportToWkt() 'LINESTRING EMPTY' >>> ogr.CreateGeometryFromWkb(ogr.CreateGeometryFromWkt('LINESTRING EMPTY').ExportToWkb()).ExportToWkt() 'LINESTRING EMPTY' >>> ogr.CreateGeometryFromWkb(ogr.CreateGeometryFromWkt('POLYGON EMPTY').ExportToWkb()).ExportToWkt() 'POLYGON EMPTY' >>> ogr.CreateGeometryFromWkb(ogr.CreateGeometryFromWkt('MULTILINESTRING EMPTY').ExportToWkb()).ExportToWkt() 'MULTILINESTRING EMPTY' >>> ogr.CreateGeometryFromWkb(ogr.CreateGeometryFromWkt('MULTIPOLYGON EMPTY').ExportToWkb()).ExportToWkt() 'MULTIPOLYGON EMPTY' >>> ogr.CreateGeometryFromWkb(ogr.CreateGeometryFromWkt('GEOMETRYCOLLECTION EMPTY').ExportToWkb()).ExportToWkt() 'GEOMETRYCOLLECTION EMPTY' The only exception is POINT EMPTY due to the lack of wkb representation for it : >>> ogr.CreateGeometryFromWkb(ogr.CreateGeometryFromWkt('POINT EMPTY').ExportToWkb()).ExportToWkt() 'POINT (0 0)' > > Fortunately the only substantial difference for ISO WKB is the type number. > > I’m starting an isowkb branch on my git repo to hold this piece of work, I > don’t think it’ll be very big. > > Then I’ll start asking about ‘m’ dimensions :) That's a fresh new land to explore... > > P. > > -- > Paul Ramsey > http://cleverelephant.ca > http://postgis.net > > On December 12, 2013 at 2:33:41 PM, Even Rouault > (even.roua...@mines-paris.org) wrote: > > Le jeudi 12 décembre 2013 21:36:42, Paul Ramsey a écrit : > > Hey all, > > Is there already a facility for writing out ISO-standard WKB in GDAL? The > > biggest difference is the wkbGeometryType number for the case of 3d > > features. OGR currently uses the old extended SFSQL adopted by PostGIS. > > ISO (naturally) did their own thing. As far as I can see, there’s no > > support there now, or is there? P. > > Hi Paul, > > no, there's no support for ISO WKB yet. We still stick to > http://home.gdal.org/projects/opengis/twohalfdsf.html > > I can imagine we could have exportToISOWkb() method in OGRGeometry*. Or we > could add an extra boolean argument bISOWkb to the existing exportToWkb(). > Not sure about WkbSize() : does the size of ISO WKB blobs differ from the > unofficial WKB ? > > Even > > -- > Geospatial professional services > http://even.rouault.free.fr/services.html -- Geospatial professional services http://even.rouault.free.fr/services.html _______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev