Federico J. Fernández wrote:
- 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.
- About "Being able to index arbitrary objects and not just points". You can 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 lot of libraries (i.e. GEOS) use this approach.
Which I can only do with R-trees and not Quadtrees, if I understand correctly. 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 results.