Brent Fraser wrote:
Is your PLSS data lines (yikes!) or areas (hopefully)? And the
shapefiles have the same attributes (or can be made that way prior to
loading into PostGIS)? Are the mining claims represented by points or
areas? If they are areas, I guess you could use the centroid in the
query.
They are areas (polygons). The shapefiles are theoretically the same,
but as with most large govt-built databases there are wee variations
that'll whack you if you don't check. So I follow Reagan's advice,
"Trust, but verify." and will fix the problems I've found already and
make each state table identical in structure.
One suggestion I've received that sounds pretty good is to pre-index the
centroids as well as the polygons. But it sounds like indexing is a very
key part of the process. Disk space and RAM is (relatively) cheap these
days while time seems to be getting more expensive.
--
Bill Thoen
GISnet - www.gisnet.com
1401 Walnut St., Suite C
Boulder, CO 80302
303-786-9961 tel
303-443-4856 fax
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