The Arr_landmarks_point_location<Arrangement,Generator> class implements a Jump & Walk algorithm, where special points, referred to as ``landmarks'', are chosen in a preprocessing stage, their place in the arrangement is found, and they are inserted into a data-structure that enables efficient nearest-neighbor search (a KD-tree). Given a query point, the nearest landmark is located and a ``walk'' strategy is applied from the landmark to the query point.
There are various strategies to select the landmark set in the arrangement, where the strategy is determined by the Generator template parameter. The following landmark-generator classes are available:
It is recommended to use the landmarks point-location strategy when the application frequently issues point-location queries on a rather static arrangement that the changes applied to it are mainly insertions of curves and not deletions of them.