title: How can gpx track add to quadtree?
body: <p>Hi
  I have a problem work whit very big gpx tracks for Android. I would like to add small parts of track to quadtree, and only this small parts draw to the display. My real problem is how implement a good quadtree structure for this problem.
  Thanks, and sorry for the language mistakes, I´m not so good in english.  </p>