> i have two question.
> one is
> topological data structure of postgresql.
> i wonder that
> how to related each spatial object-point, polygon, path..
> in postgres.
I'm not certain of your question. Most geometric objects consist of
collections of points. The exception is the circle, which consists of a
point and a radius. In order of complexity, the geometric objects are
point, lseg, line, box, path, polygon, and circle.
> another is..
> process of spatial operator.
> eg: 'contains' search points in polygon.
> how to search??
> how to relate between point table and polygon table.
> (the table has only set of coordinate..)
Hmm. Again not certain of your question, but here are some example
queries using geometric types:
CREATE TABLE pointtbl (name text, location point);
CREATE TABLE polytbl (region text, boundary polygon);
-- find which region each point is in
SELECT p.name, y.region FROM pointtbl p, polytbl y
WHERE p.location @ y.boundary;
> where reference book or site
There is a small description of each geometric type in the new User's
Guide.
- Tom
