Xapian discuss - Aug 2008 - Can xapian do geo search/calculations?

Im currently using sphinx, which has a nice geo searching interface:

If given a query and an origin (latitude, longitude, both in radians),
and told which fields correspond to latitude/longitude in the index, I
can get back results ordered by distance from that point (and get the
actual distance as well).

I would be interested in exploring xapian further, but I'm not sure if
I can get this functionality or not.  Ive been told it may be possible
with a a value range processor? Is this something anyone else has
already explored? Or know if it would even be possible?

Thanks,

Joe

On Mon, Aug 04, 2008 at 01:16:04AM -0700, Joe Noon
wrote:
> I would be interested in exploring xapian further, but I'm not sure if
> I can get this functionality or not.  Ive been told it may be possible
> with a a value range processor? Is this something anyone else has
> already explored? Or know if it would even be possible?
You could filter with two value ranges to get results restricted to a
rectangle in the coordinate system (which is in general not quite a
rectangle on the ground).

To actually get a circle, you'd want to use a MatchDecider subclass
to select points based on coordinates stored in one or two document
values.  It would probably be useful to ship a standard solution, so if
you implement something please consider sending a patch, even if it
needs a bit of work for general use.

There's also some code Richard has been working on in the geospatial
branch in SVN, but he's better placed to talk about that:

http://trac.xapian.org/browser/branches/geospatial

Cheers,
    Olly

Joe Noon wrote:
> Im currently using sphinx, which has a nice geo searching interface:
> 
> If given a query and an origin (latitude, longitude, both in radians),
> and told which fields correspond to latitude/longitude in the index, I
> can get back results ordered by distance from that point (and get the
> actual distance as well).
> 
> I would be interested in exploring xapian further, but I'm not sure if
> I can get this functionality or not.  Ive been told it may be possible
> with a a value range processor? Is this something anyone else has
> already explored? Or know if it would even be possible?
> 
> Thanks,
> 
> Joe
> 
I believe there is some work in progress on this, but it it not yet 
complete, and is waiting on those who are paying for it to give us the 
go-ahead. It's certainly possible!

Cheers

Charlie