[postgis-users] Normalizing nationalatlas.gov data

David Jantzen david at culturemob.com
Sat Jun 21 16:37:24 PDT 2008

Hi All,

I've been exploring the data up on nationalatlas.gov, in particular the
states, counties and urban areas data:


I'd like to load these into a postgis-enabled database for use by our
website.  At the same time, I'd strongly prefer a set of normalized
tables for all this information, so that we don't have redundant (and
inconsistent) state, county, city information, etc, but rather, foreign
keys.  However, many of the data sets from nationalatlas are comprised
of multiple polygon records for each entity.  For example, the
Washington state polygon data is spread across 50 rows.

Is it possible to merge the multiple polygons into a single geometry
object using postgis functions?  (I tried various operations converting
geometries to and from text without success.)  Failing that, are there
comparable data sets out there that can be normalized without turning
the polygon data into a one-to-many relation?


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