PostGIS 2.1 ST_Force_2D is depreciated

[tbonfort]

mappostgis.c uses the ST_Force_2D function, which is now depreciated with PostGIS 2.1 . Postgresql logs

WARNING:  ST_Force_2d signature was deprecated in 2.1.0. Please use ST_Force2D

[tbonfort]

@pramsey could you please have a quick sanity check at this one? The aim is to stop using the deprecated st_force_2d for recent postgis version, or leave out the force_2d call completely if PROCESSING "FORCE2D=off" is added to the layer.

[pramsey]

The code on its own looks fine, but it's going to run into a mess in the WKB handler, which expects 2D inputs only. So that code will also need to be touched a bit to recognize 3D wkb types and then do the Right Thing when they arrive.

[tbonfort]

@pramsey I see it more as an optional parameter you can add to avoid going through force_2d when you know that your geometries are not in 3D. It's off by default, and can be documented as resulting in undefined behaviour if used with 3D geometries.

[pramsey]

Ah, I see. A bit scary, since people might easily assume that it means support for 3d, rather than lack of 2d forcing. But I think (looking at the code) the result won't be a crash but an error... pretty sure.