[postgis] SFSQL Metadata Views

[Dave Blasby]

>However, currently there is no real support for metadata of any kind.
> 
> The SF-SQL specification includes two "Feature Table Metadata Views":
> 
>  o GEOMETRY_COLUMNS: Associates geometry columns with a spatial reference
>    system id, a geometry type (restricting the columns to lines for instance),
>    and a dimension.
> 
>  o SPATIAL_REFERENCE_SYSTEMS: Associates spatial reference system id with
>    their well known text equivelent.
....


I've been looking into that today, and we could probably write some
triggers and stored procedures to keep GEOMETRIC_COLUMNS updated.

We'll need to have some way of restricting a GEOMETRY column to be, say,
a LINESTRING.  I dont want to have to read a system table on every
INSERT or UPDATE.  Any ideas?

We'll also have to do something with the Spatial Reference System.  I'm
actually looking at that right now since I want to add a length()
function that works on a ellipsoid.  

dave

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