> I'm interested in using PostgreSQL as a back end spatial RDBMS.
> Having just stumbled across PostGIS, I'm wondering what it offers above
> the spatial functionality available with v7.1 of PosgreSQL?
I suggest that you visit http://postgis.refractions.net for more
details. Release 0.5 is imminent (hopefully tommorrow) and has many
more features than whats currently documented in 0.2.
But, back to your question,
+ PostgreSQL types are 2d, PostGIS are 2d and 3d.
+ PostgreSQL only supports point, line, and very simple polygons
+ PostGIS support the OpenGIS WKT types, and their 3d equivalents
POINT, LINESTRING, POLYGON, GEOMETRYCOLLECTION,
MULTIPOINT, MULTILINESTRING, MULTIPOLYGON
+ PostGIS polygons support holes
The major differences is that the PostGIS geometry type can be either a
POINT, LINESTRING, POLYGON, MULTIPOINT, MULTILINESTRING, MULTIPOLYGON or
a combination (thats what a GEOMETRYCOLLECTION is). These types more
accurately reflect spatial information needs than the basic types in
+ PostGIS supports full indexing of the geometry types.
+ The PostgreSQL types, I believe, do not all support indexing.
3. Binary Access
+ PostGIS supports endian-aware binary access (OpenGIS Well Known