Efficient trajectory queries under the Fréchet distance (GIS Cup)

Kevin Buchin, Yago Diez, Tom van Diggelen, Wouter Meulemans
2017 Proceedings of the 25th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems - SIGSPATIAL'17  
Consider a set P of trajectories (polygonal lines in R 2 ), and a query given by a trajectory Q and a threshold ε > 0. To answer the query, we wish to find all trajectories P ∈ P such that δ F (P, Q) ≤ ε, where δ F denotes the Fréchet distance. We present an approach to efficiently answer a large number of queries for the same set P. Key ingredients are (a) precomputing a spatial hash that allows us to quickly find trajectories that have endpoints near Q; (b) precomputing simplifications on all
more » ... trajectories in P; (c) using the simplifications and optimizations of the decision algorithm to efficiently decide δ F (P, Q) ≤ ε for most P ∈ P.
doi:10.1145/3139958.3140064 dblp:conf/gis/BuchinDDM17 fatcat:e4laefsejfc5daoposrp773ilm