Re: Points, Circles, Indexes, and query-by-Radius?

On Thu, 2 Aug 2001, Bryan Field-Elliot wrote:

> I'm developing a GIS system on PostgreSQL.  I need to store a table of
> points (latitude and longitude), and do queries such as "return all
> points enclosed with the given circle ((X,Y),R)".
>
> The "point" data type looks convenient, however, it doesn't appear to be
> indexable.
>
> Can anyone tell me what the preferred, recommended strategy for this
> design pattern is, with respect to PostgreSQL? One which makes good use
> of indices, if possible (realizing that I personally don't know a good
> way to index for a radius search).
>
> For extra credit, it would be nice if I could store circles instead of
> points, and issue queries like the following:
>
> "given a circle ((X,Y),R), return all circles which share some common area"
>

I haven't yet played with it, but look at PostGIS, an add-on for
PostgreSQL which claims to have better spatial indexing & querying
capabilities for geometric datatypes.

As an aside, can anyone comment on the likelihood of this becoming a part
of mainstream pgsql? Or what is currently happening with pgsql spatial
support, especially regarding fmaps development?


Cheers,

  Brent Wood