Not quite clear what you are trying to do 1) Do you have table a with n rows and table b with m rows (each having the same fields) and you want table c with (m + n) rows. This is a regular old SQL union and not a spatial union So would be done with INSERT INTO c(field1,field2, .., the_geom) SELECT a.field1, a.field2, ... a.the_geom FROM a UNION ALL SELECT b.field1, b.field2, ... b.the_geom FROM b; or are you trying to do a spatial union or intersection and in what case what records are you trying to group together into a geometry or join by There are so many permutations of spatial unions and spatial intersections - that its hard to give an answer without having more details about what you are trying to accomplish. e.g a spatial intersection result may looks something like this 2) INSERT INTO c(field1,field2, field3,.., the_geom) SELECT a.field1, a.field2, b.field1 as field3 .. ST_Intersection(a.the_geom, b.the_geom) as the_geom FROM a INNER JOIN b on (a.zip = b.zip (or whatever field) and ST_Intersects(a.the_geom, b.the_geom) Hope that helps, Regina
________________________________ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of K. Pandey Sent: Tuesday, March 25, 2008 11:51 PM To: [email protected] Subject: [postgis-users] Spatial Analysis/Union of shapefiles I want to perform union of two shape files using postgresql. I converted the shape files to postgres tables using shp2pgsql utility. How to perform the union/intersection of these two tables. Once the union/intersection is completed, I can convert the union file back to shapefile using pgsql2shp utility. -- Kamal Pandey Dehradun ----------------------------------------- The substance of this message, including any attachments, may be confidential, legally privileged and/or exempt from disclosure pursuant to Massachusetts law. It is intended solely for the addressee. If you received this in error, please contact the sender and delete the material from any computer.
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