[postgis-users] newbie question about geometry

[trevorw]

On Fri, 15 Sep 2006 09:35:30 -0600
"Vincent J. Troisi" <Vincent.Troisi at Colorado.EDU> wrote:

> I have some geospatial data I'd like to store  in postgresql and
> use postgis operations on the data. The  records  contain  many 
> attributes, but
> the geometry is defined by 4 corner points (latitude in degrees from
-90 
> to 90
> and longitude in degrees from 0 to 360) with lines between the points
as
> great circle arcs. I want to create spatial queries based on 4 or more

> point polygons
> of any projection that will enable me to test whether the polygon
stored
> in the database overlaps (contains, overlaps or intersects) the
polygon of
> the query.
> 
> Questions:
>     Can I store longitudes as 0-360 or do I need to use the range -180
> to 180?

AFAIK -180 - 180 is necessary.

If you want to re-project into functional areas your lat /
lon 4 corner areas you will need to be broken up into short segments. 
To do this you could create a grid and intersect the polygons. This
should be fairly easy to do with a text editor and creating geometry
from text or you can do it easily in GRASS and import it into PostGIS.

If you will note the postgis documentation there are functions for
contains, overlap, and intersection. 

T
-- 
Trevor Wiens