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This year will be the 6th GIS-focused algorithm competition, GISCUP 2017, co-located with the 2017 ACM SIGSPATIAL GIS conference. ACM SIGSPATIAL hosts an annual algorithm contest with the goal of encouraging innovation in a fun way. The winners will be announced at the ACM SIGSPATIAL GIS conference in November 2017. Contest participants will submit original computer programs to be evaluated by the contest organizers on common datasets.

This year’s contest will focus on the growing research area of trajectory computing. Massive amounts of spatial trajectories are generated nowadays by smartphones, infrastructure, computer games, natural phenomena, and many other sources. A trajectory consists of a time series of locations with the assumption that some sort of interpolation (often piecewise linear) is reasonable. In this way, trajectories are one-dimensional geometric objects, but their representation in computer systems is usually zero-dimensional as a series of pairs of location and time, for example: .

Trajectory similarity is a very basic problem when dealing with this type of data and many different ways of comparing trajectories have been proposed. In this challenge, we concentrate on a very intuitive measure called **Fréchet distance** with hard computational complexity, but superior quality in theory and practice.

The Fréchet distance is defined as the minimal length of a leash connecting a dog on one trajectory with its owner on a second trajectory, both never moving backwards. For this challenge, the "true" Fréchet distance shall be used, though teams are free to exploit the existing approximations including the Discrete Fréchet distance as they wish. The challenge for this year consists of finding and combining spatiotemporal indexing schemes with efficient algorithms for Range Queries in very large databases of trajectories. The approaches will be evaluated on a multitude of real and synthetic datasets, a sample datasets can be found on the download page page.

In summary, the key topics that are being addressed in this year’s cup are the following:

Spatio-temporal Big Data

Trajectory Computing

Computational Geometry

Indexing and Retrieval in Spatial Computing

The top three teams will be provided with cash and / or other prizes. In addition to these prizes, the top three teams will be invited to submit a four page paper for a contest paper session to be held at the 2017 ACM SIGSPATIAL GIS conference. These papers will be subject to review and acceptance by the contest organizers, but it is expected that each of the top three teams will have their paper in the conference proceedings and a ten-minute presentation in the contest session. At least one team member of each winning team must register for the 2017 ACM SIGSPATIAL GIS conference.