CGAL 5.4.4  Quadtrees, Octrees, and Orthtrees

#include <CGAL/Quadtree.h>
Alias that specializes the Orthtree
class to a 2D quadtree.
These two types are exactly equivalent:
Quadtree<GeomTraits, PointRange, PointMap>
Orthtree<Orthtree_traits_2<GeomTraits>, PointRange, PointMap>
.Orthtree
.GeomTraits  must be a model of Kernel 
PointRange_  must be a model of range whose value type is the key type of PointMap 
PointMap  must be a model of ReadablePropertyMap whose value type is GeomTraits::Point_2 