[postgis-users] Intersect Query Issue
Jerod Clabaugh
jclabaugh at mac.com
Wed Jun 1 15:01:38 PDT 2005
All:
I am trying to get the area as acres from the overlap of 2 polygons.
I have 2 polygon tables, shape.pa and shape_incursion_2005. I used
the query below and got an answer but its not correct. Its not
providing the correct area for the overlapping area post-clipping,
but rather pre-clipping.
SELECT (area(shape_incursion_2005.the_geom)* 0.0002471) as acres,
intersection(shape_incursion_2005.the_geom, shape_pa.the_geom) FROM
shape_pa, shape_incursion_2005 WHERE
intersects(shape_incursion_2005.the_geom, shape_pa.the_geom) AND
shape_pa.name = 'Caracol'
In ArcGIS, I would select the polygon I wanted to compare
(shape_pa.name = 'Caracol') and then clip the other table's
overlapping polygons onto it and then calculate the area...
Any ideas on what I am doing wrong?
Thanks in advance,
Jerod Clabaugh
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