[mapserver-users] msOGRFileNextShape(): OGR error. TopologyException: side location conflict

[Friend Vn 2000]

Thanks Frank, Daniel and Oliver,
I'm sure that my data has topology errors. I'm using pure MS4W and my method is PHPMapscript. My small application is only for zoom, pan.
In my experience, I also think MapServer or any mapping engine can draw a request map without checking its topology for legal or not. And my .mdb file runs well in ArcMap or ArcCatalog, and I think they don't take notice of topology when playing my file.
Best regards,
 
--- On Tue, 8/18/09, Frank Warmerdam <warmerdam at pobox.com> wrote:


Friend,

I believe this error is coming from GEOS and likely occurs when the geometries
from the file are translated into GEOS format in order to do a spatial
comparison test against the map view within OGR.

This likely is due to a linestring or polygon being invalid - perhaps due
to self-intersection.

Actually, I'm surprised that things would dip into the GEOS geometry
comparisons. MapServer is careful to only set rectangular spatial filters
and OGR is supposed to short circuit this case to avoid GEOS.  I'm not really
sure why you end up in GEOS.  Are you doing any other fancy stuff that
might end up in GEOS?

If you could boil this down to something similar I could use to reproduce
the problem, I would be willing to have Chaitanya look into it.  It would
need to be filed as a GDAL ticket.

Best regards,
-- ---------------------------------------+--------------------------------------
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent




      
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