[postgis-users] ST_Touches and line segment

Martin Davis mbdavis at refractions.net
Thu Mar 19 09:28:03 PDT 2009

Kevin Neufeld wrote:
> If you have overlapping polygons then use ST_Relate with a custom 
> matrix.  IE. ST_Relate(g1, g2, '****1****') will return TRUE for all 
> geometry pairs where the intersection of the boundaries occur on a 
> line (1).
You need to know the type of the input geometries.   The above pattern 
will work for polygons, but not for lines.  The L/L and P/L situation 
require different patterns:

L/L: 1********
P/L: ***1*****
> Cheers,
> Kevin
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Martin Davis
Senior Technical Architect
Refractions Research, Inc.
(250) 383-3022

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