Brisaboa, Nieves R.Gómez-Brandón, AdriánNavarro, GonzaloParamá, José R.2017-02-232017-02-232016-09-21Brisaboa N.R., Gómez-Brandón A., Navarro G., Paramá J.R. (2016) GraCT: A Grammar Based Compressed Representation of Trajectories. In: Inenaga S., Sadakane K., Sakai T. (eds) String Processing and Information Retrieval. SPIRE 2016. Lecture Notes in Computer Science, vol 9954. Springer, Cham0302-97431611-3349http://hdl.handle.net/2183/18176The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-319-46049-9_21[Abstract] We present a compressed data structure to store free trajectories of moving objects (ships over the sea, for example) allowing spatio-temporal queries. Our method, GraCT, uses a k2k2 -tree to store the absolute positions of all objects at regular time intervals (snapshots), whereas the positions between snapshots are represented as logs of relative movements compressed with Re-Pair. Our experimental evaluation shows important savings in space and time with respect to a fair baseline.engTrajectories of moving objectsGraCTRepresentation of trajectoriesconference outputopen access10.1007/978-3-319-46049-9_21