Hi, If I understand the question correctly, you want to identify polygons which are outside of a polygon (including inside the hole of another polygon) but within the outer polygon perimeter.
You can do this with a self relation (join a table to itself). Something like: select t1.name from table t1, table t2 where not ST-Within (t1.geom, t2.geom) and ST_Within(t1.geom, ST_Boundary(t2.geom)); To get the count of these, rather than the list of names, try: select count(t1.name) from table t1, table t2 where not ST-Within (t1.geom, t2.geom) and ST_Within(t1.geom, ST_Boundary(t2.geom)); HTH, Brent Wood Sent: Thursday, October 28, 2010 6:07 AM To: PostGIS Users Discussion Subject: [postgis-users] Selecting polygons circled by one only polygons Hi, I have a table of polygon where every polygon can be holed. And in the hole can be inside another polygon (another record of the table, no multipolygons). I need to detect all the polygon that are inside a hole of another polygon. Initially I think this was easy but after some test I notice this is not so easy because the polygon inside the hole is formerly disjoint from the polygon with hole. For more example I don't search the polygon that are full circled by more than 1 polygon, but only the polygon circled by 1 only polygon There is some method to detect this type of situations ? Thx, Andrea peri. -- ----------------- Andrea Peri . . . . . . . . . qwerty àèìòù ----------------- -----Inline Attachment Follows----- _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
_______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
