“…There is a major need to have full access to underlying real road networks to experiment and evaluate various algorithms, which include shortest path queries [14,28,35,36,38,39], k-nearest-neighbor queries [4,11,12,13,17,19,37,40], reverse nearest neighbor query [15,30], range queries [3], skyline query [5,33], among others (e.g., [16,32,39]). Unfortunately, it is always challenging to get such real road network, which imposes a major obstacle in advancing the research in such algorithms.…”