The Area Code Tree for nearest neighbour searching

In this paper, we propose the Area Code Tree for nearest neighbour searching. It is a trie-type structure that stores points of interest (POIs) that are represented in area code format. An area code is a sequence of digits that indicate the relative location in space of a POI. We present the area code calculation, insert, and nearest neighbour search algorithms. We also present the results of a preliminary evaluation on the nearest neighbour search performance. We find that the efficient search times make the Area Code Tree an excellent candidate for continuous nearest neighbour processing for location-based services.