Subject: Re: [boost] Geometry and spatial indexes, my opinion
From: Federico J. Fernández (federico.fernandez_at_[hidden])
Date: 2008-10-09 08:07:44
> - You are able to find all elements within a certain range, if you mean by
>> range a box. Or you can use a box and then refine the result filtering out
>> the elements that are not in your area.
> I meant it in a more abstract way. Usually a range is defined by a circle
> (rather than a box), but it could also be an area defined arbitrarily, so
> why not make it work with any geometrical object, using geometry::intersect
> and geometry::within in place of your overlap function?
> Maybe it would be more practical if geometry provided an overlap
> (not-completely-within) test function. Maybe having a search where you
> search for elements that are completely within an area is interesting too?
> In that case you might as well parameterize the criteria.
I understand. That's the plan, but it's not yet ready, I just wanted to
point out that there is some basic functionality about this.
insert the envelopes of arbitrary geometries and a pointer to the real
>> object as the data. Maybe it's not the best interface to do this, but a
>> of libraries (i.e. GEOS) use this approach.
> - About "Being able to index arbitrary objects and not just points". You
> Which I can only do with R-trees and not Quadtrees, if I understand
> It will still lead to approximations when computing distances and the like
> though, the actual object may be more far away than its minimal axis-aligned
> bounding box and thus the nearest neighbor search might return wrong
Yes, but we should be careful about the performance penalty of having
arbitrary geometries in the index and using different algorithms for
distances and other operations.
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