“…Moving objects were usually abstracted as points (Ranu et al, 2015), single continuous polynomials (Ni and Ravishankar, 2007), or non-regulated sequences of roads in transportation networks (Sandu Popa et al, 2011). Then, these objects were indexed by the tree's derivatives, for example, B + -trees (Sandu Popa et al, 2011), R-trees (Yue et al, 2018), 3D R-trees (Xu et al, 2018), FN (fixed network) R-trees , PA-trees (Ni and Ravishankar, 2007), and grid trees (Yan et al, 2015). These tree-based indices could facilitate efficient queries on moving objects.…”