[postgis-users] Is my query planner failing me, or vice versa?

[strk at refractions.net]

This is also ready in GEOS CVS.
ConvexHull has been put in sync with JTS in semantic terms,
but also deep improvements in memory management have been
committed. I didn't profile results, but I'm sure we're 
getting better (I love not having to maintain an ABI compatibility).

--strk;

On Tue, Dec 13, 2005 at 05:35:39PM -0800, Martin Davis wrote:
> > Martin, postgis worst case for Distance is O(nm), what should 
> > we expect from JTS ?
> 
> In JTS distance uses essentially the same algorithm as PostGIS, so it's
> O(nm).  I think you can do better than this with some fancy algorithms,
> but I haven't implemented those ideas yet.
> 
> It's worth noting that what is really being asked is whether
> g.isWithinDistance(h, 5000) = true.  IsWithinDistance allows even more
> optimization than distance - but unfortunately JTS doesn't implement
> those optimizations yet (apart from a simple bounding box check).
> 
> The convex hull idea is a good one.  By the way, I've been doing some
> work on the JTS convex hull routines recently, and made a huge speedup
> over the old one.  Strk, might be work taking a look at that code to see
> about porting it to GEOS.  Shouldn't be too hard to do - the algorithm
> is basically the same, it's just more carefully implemented.
> 
> Martin Davis, Senior Technical Architect
> Vivid Solutions Inc.      www.vividsolutions.com
> Suite #1A-2328 Government Street Victoria, B.C. V8T 5G5
> Phone: (250) 385 6040 - Local 308 Fax: (250) 385 6046
> 
> 
> > -----Original Message-----
> > From: strk at refractions.net [mailto:strk at refractions.net] 
> > Sent: December 13, 2005 4:54 PM
> > To: PostGIS Users Discussion
> > Cc: Martin Davis
> > Subject: Re: [postgis-users] Is my query planner failing me, 
> > or vice versa?
> > 
> > 
> > On Tue, Dec 13, 2005 at 05:08:07PM -0700, Jessica M Salmon wrote:
> > > Strk -
> > > 
> 
> >