[postgis-devel] patch : TIN & POLYHEDRALSURFACE

Robert W. Burgholzer rburghol at vt.edu
Mon Sep 24 10:21:25 PDT 2007

My reaction is that this is a very good thing indeed. Some of the issues
regarding rasters, at least in terms of elevation rasters, could be ameliorated
with the TIN approach.

My $0.02,

Quoting Mathieu Le Serre <mathieu.leserre at camptocamp.com>:

> Hi,
> A few month ago, we already discussed here about 3D storage and PostGIS,
> (cf
> We made a patch to add such new geometries to PostGIS.
> It implements TIN and POLYHEDRALSURFACE as described in
> OGC SFS1.2 standard.
> These geometries are specific MULTIPOLYGON that
> describe 3D surfaces and 3D volumes.
> Currently, we got the following functions to work for 3D geometries:
> - asEwkb
> - asEwkt
> - asGml
> - asSvg (2D output only)
> - asX3d.
> This last function enables exporting 3D geometries to the X3D format.
> I also provide a patch for GEOS to implement the isValid function
> for TIN and POLYHEDRALSURFACE. It checks if feature faces
> are well connected and well oriented.
> A presentation around this work will be done in FOSS4G
> <http://www.foss4g2007.org/presentations/view.php?abstract_id=224>
> PostGIS implementation consideration:
> There were already 15 geometries types and I needed to add two. But geometry
> types were coded on 4 bits only...
> In order to implement these geometries,  I decided to drop three unused
> They were not present in the postgis parser, and were described as
> "Invalid types" in the file liblwgeom.c.
> Any comments and/or reactions would be greatly appreciated.
> Best regards,

Robert W. Burgholzer
Finding the occasional straw of truth awash in a great ocean of confusion and
bamboozle requires intelligence, vigilance, dedication and courage.  But if we
don't practice these tough habits of thought, we cannot hope to solve the truly
serious problems that face us -- and we risk becoming a nation of suckers, up
for grabs by the next charlatan who comes along.
-- Carl Sagan, "The Fine Art of Baloney Detection," Parade, February 1, 1987

Online Workout Editor:
Gardening Blog:
Age Group Distance Swimming Blog:

More information about the postgis-devel mailing list