Tilmann Singer wrote:

We are using this data which seems to be fairly extensive and
accurate, and is free:

http://earth-info.nga.mil/gns/html/gis_countryfiles.htm

We use that, but it is only non-US, so we combine it with this:

  http://geonames.usgs.gov/domestic/download_data.htm

We also have a hodge-podge of other sources, but those are the main ones. (By the way, we have found USGS to very amenable to dumping their data in arbitrary ways. Those state files essentially try to fit everything into a single CSV format, but they have given us other custom dumps.)

Note that both of these main sources have multiple names for the same location, so our schema is highly normalized - we have a separate table for names (so the string "Springfield" occurs in only one place :). Because we are interested in all sorts of geographic entities, not just city/state/country, we have only a single table for these, with fields for type, lat/long, primary name, and a few other things. All other relationships are represented in separate linking tables, using our internal IDs for locations and names, e.g., location_has_name, location_contained_in_location, etc. As far as FIPS and ISO codes are concerned, we have a separate table mapping (locationID, standards body) to codes.

We are interested in sharing this stuff, so I'd be happy to pass along the schema and/or the data, although all of it is kind of beta.

- John D. Burger
  MITRE



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