[postgis-users] Intersection bug

[strk at refractions.net]

If your query box falls into a polygon hole the result will be
the empty geom (it's topological intersection!).

If by 'gets aborted' you mean you receive an error this has to do
GEOS/JTS algorithms throwing exceptions, error message should tell
you more; they are usually due to invalidity of input geometries.

Finally: what are you really doing ? Show us a query.

--strk;

On Thu, Mar 24, 2005 at 02:57:14PM -0700, Sean M. Montague wrote:
> Has anyone had a problem with intersecting a poly and getting a result
> one time and nothing another?  In my SVG, I have set up zoom levels,
> when the map reaches a certain level, I intersect the data in PostGIS
> with the user defined zoom box, and recreate the map, allowing me to add
> detail without increasing map size.  But there seems to be a bug in the
> intersection query.  It seems that if my zoom box happens to intersect a
> poly a certain way, the whole query gets aborted and nothing is
> returned.  I've potentially already detected what is happening, but I'm
> not sure how to simplify my example.  I've done so already, but I only
> know how to use php with PostGIS, so any example I forward will be in
> php.  I use SVG to display the results.  Only way I know how to. 
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