[gdal-dev] ISO WKB

Paul Ramsey pramsey at cleverelephant.ca
Thu Dec 12 15:24:25 PST 2013


Sounds good to me. Is "wkbVariantOGC" the variant currently implemented ? Is 
our 3D support really compliant with an OGC standard ? 
Not really anymore, since SFSQL 1.2 defined OGC into sync with ISO. We’re in compliance with the old guidance that was passed and promptly forgotten in the period between SFSQL 1.1 and 1.2. Nothing wrong with that, we can call it something else (I guess?)

> 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 ? 
Nope, you’re right. The empty support is implicitly tied to the understanding that numPoints == 0 means empty and numRings == 0 means empty and numGeoms == 0 means empty, rather than an IsEmpty() test.

The GeoPackage document actually specifies a representation for POINT EMPTY,  "In GeoPackages these points SHALL be encoded as a Point where each coordinate value is set to an IEEE-754 quiet NaN value”.

P
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