[postgis-users] Spatial Operators

Marcus C. England marcuscengland at gmail.com
Fri May 30 16:44:47 PDT 2008

Hi all,

Well, moving to PostGIS as a spatial data format has helped a lot with 
trying to learn SQL, but I still have problems with the SQL syntax for 
spatial operators. Here is what I want to do:

   (1) basin_grading: polygons representing the impact area of a 
proposed basin, plus 100' and 200' buffers. Whether the polygon 
represents grading or a buffer is stated in attribute column "land_use"

   (2) new_vegetation: polygons representing vegetation communities. The 
community names are in attribute column "veg_".

The problem:

I would like to use sql to generate a table of vegetation types and the 
acreages impacted by each land use in "basin_grading". I would assume 
you would use "ST_Intersection", but I have tried to alter quite a few 
examples of its use that I found on-line and I always get an error about 
my syntax.

Tips, pointers, etc are greatly appreciated.


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