[postgis-users] problems cleaning geometry - other options?

[Mark Cave-Ayland]

William Kyngesburye wrote:

> I'm trying to fix some polygons-with-holes imported from shapefiles 
> where the main polygon is not the first in the list, one of the hole 
> polygons is, making them invalid.
> 
> These are 3D multipolygons - imported from the SRTM SWBD shapefiles 
> (with GDAL). (file w162n55n if anyone wants to try)
> 
> The cleanGeometry funtion at:
> 
> http://postgis.refractions.net/support/wiki/index.php?CleanPolygons
> 
> isn't working, I get an error:
> 
> =>select astext(cleangeometry(wkb_geometry)) from swbd where cell = 
> 145018 and wb = 353;
> NOTICE:  Hole lies outside shell at or near point -161.201 55.9992 0
> CONTEXT:  PL/pgSQL function "cleangeometry" line 15 at IF
> ERROR:  Dimensions mismatch in lwcurve
> CONTEXT:  PL/pgSQL function "cleangeometry" line 19 at assignment
> 
> I tried forcing the geometry to 2D (st_force_2d()) and I get a different 
> error:
> 
> NOTICE:  Hole lies outside shell at or near point -161.201 55.9992
> CONTEXT:  PL/pgSQL function "cleangeometry" line 15 at IF
> ERROR:  Exception in LWGEOM2GEOS: curved geometry not supported.
> CONTEXT:  PL/pgSQL function "cleangeometry" line 19 at assignment
> 
> These shapefiles don't have curved geometry (I'm not sure it's supported 
> in shapefiles).
> 
> 
> I wonder if there is a simpler operation that could reorder sub-polygons 
> to put the one that contains all the others first?  And would it be 
> faster or slower?


Hi William,

Which versions of PostgreSQL/PostGIS is this? Since the error message in 
question is only in the lwcurve curve, it sounds like an internal error. 
  If you can extract a standalone test case and post it on the bug 
tracker, I'll take a look at it.


ATB,

Mark.

-- 
Mark Cave-Ayland
Sirius Corporation - The Open Source Experts
http://www.siriusit.co.uk
T: +44 870 608 0063