range searching algorithms

[Stef Pillaert]

Hello,

I'm trying to program some range searching jobs (like: looking for points
falling in a rectangle or a sphere, looking for intersection of segments,
determining whether a point is inside a polygon, ...) Is there someone who
has done this before in octave (or matlab? some kind of toolbox, maybe?).
The main problem is to build a decent searching-tree (using structures?).

Thanks for your time,

Stef.