[postgis-devel] st_dwithin, st_within, st_dcompletlywithin

[Paragon Corporation]

Oh that's what that is.  Hmm and I think its already ported to PostGIS,
though would be interesting to compare the speeds and results.  Since the
current one in trunk is a GEOS call and Nicklas' would be a native PostGIS.

http://trac.osgeo.org/postgis/ticket/209 

Paul are you hmm planning add this to the manual -- I see you closed it?  I
don't recall seeing it in the 1.5 docs or were we waiting for GEOS to be
patched first?

Thanks,
Regina


-----Original Message-----
From: postgis-devel-bounces at postgis.refractions.net
[mailto:postgis-devel-bounces at postgis.refractions.net] On Behalf Of Martin
Davis
Sent: Wednesday, July 08, 2009 6:14 PM
To: PostGIS Development Discussion
Subject: Re: [postgis-devel] st_dwithin, st_within, st_dcompletlywithin

That distance metric is known as the Hausdorff Distance.  It's implemented
in JTS, and probably in GEOS as well.

nicklas.aven at jordogskog.no wrote:
>
>
> A function that gives the answer to for example:
> "How far away from France can you get in Belgia"
> To answer that we have to store compare the shortest distance to
> geometry2 from each vertex in geometry1 and finaly find wich vertex in
> geometry1 that has the highest "mindistance" to geometry2.
> Hope the idee is possible to understand. Is it of any use?

--
Martin Davis
Senior Technical Architect
Refractions Research, Inc.
(250) 383-3022

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