PostGIS is an open source software that spatially enables the PostgreSQL database. I have been using PostGIS for several years and it has served me well personally as well as in a couple of GIS implementation projects. It is easy to use and I really like being able to create spatial tables and perform spatial queries and analysis all from the SQL prompt. I could string a number of the statements into a script for automated batch processing. An example PostGIS spatial query is shown below:
create table demand as
select a.postcode, a.telno, a.acctclass, a.premisenumber, a.premiseaddress, a.avgbill, a.acctclass, a.x, a.y, a.demandtype, b.polygonid
from custdata a, demandpolygon b
where (a.the_geom && b.the_geom) and
order by b.polygonid
The field the_geom is the geometry field of the tables; the operator ' &&' is similar to Oracle's first pass rough filter while intersects is a spatial operator.
One of the problems that I face is the lack of a good graphical user interface for viewing and manipulating spatial data in PostGIS. I have to export data in Shape file format using the PostGIS utility pgsql2shp for viewing in GeoMedia.
However, I have just seen the Intergraph 2008 GeoMedia Product Updates presentation and I am pleased to see that a PostGIS Data Server will be developed as part of a minor release of GeoMedia 6.1. It is not known whether it will be a Read only or Read/Write data server. Let's hope it is R/W. Here is a crop of a slide below: