R package nabor: Wraps ’libnabo’, a Fast K Nearest Neighbour Library for Low Dimensions. An R wrapper for ’libnabo’, an exact or approximate k nearest neighbour library which is optimised for low dimensional spaces (e.g. 3D). ’libnabo’ has speed and space advantages over the ’ANN’ library wrapped by package ’RANN’. ’nabor’ includes a knn function that is designed as a drop-in replacement for ’RANN’ function nn2. In addition, objects which include the k-d tree search structure can be returned to speed up repeated queries of the same set of target points.