This project can be used as a framework, or you can just drag KDTree.h, KDTree.m, KDNode.h, KDNode.m, KDLeaf.h, and KDLeaf.m into your existing project. To use it, just instantiate a KDTree object and pass it a 2-Dimensional array with the method -(id)initWithArray:(NSArray*)array. The 2D array should be an array of arrays that contain any number of points (your coordinates) and the final element must be metadata (it can be any type of object: NSString, NSArray, or your own custom object). So for a 3D tree the array would look like: {{1, 2, 3, metadata}, {3, 6, 7, metadata}, {4, 1, 7, metadata}, ... }. The tree can then be searched with the method -(KDLeaf*)findApproximateNearestNeighbor:(NSArray*)coordinates, or -(KDLeaf*)findNearestNeighbor:(NSArray*)coordinates. Each method takes an NSArray of numbers (e.g., for a 3D tree {3, 4, 1}) and will return the KDLeaf with the nearest coordinates, you can then get the coordinates of the KDLeaf (it is an NSArray called: points) and the metadata (it is an id: metadata). findApproximateNearestNeighbor will be incredibly fast, but not always accurate. findNearestNeighbor is accurate, but can be anywhere from a little bit to much slower.