[postgis-users] Best Practices for Configuring Large Data Sets

Bill Thoen bthoen at gisnet.com
Fri May 28 09:40:47 PDT 2010

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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