Why is HierarchicalArray2D used in openslam_gmapping?
openslam_gmapping uses HierarchicalArrary2D to store the map. HierarchicalArray2D is something like a 2D array, and each cell of it is a 2D array again.
So if a map's size is 256 * 256, size of HierarchicalArray2D is 8 * 8, and each cell of it is a 32 * 32 2D array.
I'm a bit confused about the data structure above, why don't we use an Array2D directly? Does HierarchicalArray2D has any advantages?
Thanks a lot!