[postgis-users] SRID for analyzing a USA national data set in Meters

[Jeremy Dunck]

On 4/2/07, David William Bitner <david.bitner at gmail.com> wrote:
> CREATE OR REPLACE FUNCTION utmzone(geometry)
...
>   LANGUAGE 'plpgsql' VOLATILE;


This function is guaranteed to return the same result as long as
spatial_ref_sys doesn't change, and so could be classified as:
  LANGUAGE 'plpgsql' IMMUTABLE;
for better performance.

Cheers,
  Jeremy