[geos-devel] Dimension of EMPTY geoms

Mateusz Loskot mateusz at loskot.net
Mon Dec 4 10:01:16 EST 2006

Markus Schaber wrote:
> Hi, Mateusz,
> Mateusz Loskot wrote:
>> AFAIK OGC SFS does say nothing about how to report dimension of empty
>> geometry.
>> OGC SFS reserves values 0, 1, and 2 for dimensions of non-empty
>> geometry, so I'd suggest to use negative value.
> Don't confuse OGC dimension (geometrical dimensionality of the described
> object, Points have 0, LineStrings have 1, and Polygons have 2) and
> coordinate dimension (number of ordinates per vertex, which can be 2,3
> or 4 in PostGIS).


You are perfectly right! Sorry, I've read the message too fast.

Mateusz Loskot

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