Marcus, 1) You could create your table prior to populating it, and include a column that is type "SERIAL", this will create an autogenerated integer identifier that you could name "gid" if you so desired.
2) select area2d(Intersection(f.the_geom, c.the_geom)) ... NOTE: You will have to convert this area2d result from the units of your map projection into acres 3) ST_intersection and intersection are the same, the new (ST_*) naming convention was recently added, for reasons that I do not know but assume that they were good ones. HTH, Robert -----Original Message----- From: [EMAIL PROTECTED] on behalf of Marcus C. England Sent: Tue 6/3/2008 2:57 PM To: PostGIS Users Discussion Cc: Subject: [postgis-users] Intersection - No GID Hi all, I figured out how to use Intersection and get a resulting table with apparently correct results using the example from the PostGIS website: CREATE TABLE new_fields AS SELECT Intersection(f.the_geom, c.the_geom) AS the_geom, f.attr1, f.attr2, c.clu_name FROM fields f, clu c WHERE f.the_geom && c.the_geom AND Intersects(f.the_geom, c.the_geom) However, this example does not create a gid column and I therefore can not view the results in a GIS program. Is there a way to create a gid column after-the-fact? Optional questions for those feeling super-helpful: (1) How should the above SQL be rewritten to include gid in the resulting table? (2) I know that eliminating the first line will simply give me a table spit onto the SQL results in pgAdmin. How do I alter the SQL above to give me the acreages rather then a list of the geometries? I can get the acreages from the table resulting from the above, but I can't figure out how to skip the step of creating a table. (3) What is the syntax using ST_Intersection rather than Intersection? thanks, Marcus _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
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