Isocontours in road networks represent the area that is reachable from a source within a given resource limit. We study the problem of computing accurate isocontours in realistic, large-scale networks. We propose isocontours represented by polygons with minimum number of segments that separate reachable and unreachable components of the network. Since the resulting problem is not known to be solvable in polynomial time, we introduce several heuristics that run in (almost) linear time and are

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... ple enough to be implemented in practice. A key ingredient is a new practical linear-time algorithm for minimum-link paths in simple polygons. Experiments in a challenging realistic setting show excellent performance of our algorithms in practice, computing near-optimal solutions in a few milliseconds on average, even for long ranges. 1 Introduction How far can I drive my battery electric vehicle (EV), given my position and the current state of charge?-This question can be answered by a map visualizing the reachable region. This region is bounded by isocontours representing points that require the same amount of energy to be reached. Isocontours are typically considered in the context of functions f : R 2 → R, in our case describing the energy necessary to reach a point in the plane. However, f is defined only at certain points, namely vertices of the graph representing the road network. We have to fill the gaps by deciding how an isocontour should pass through regions between roads. The fact that the quality of the resulting visualization heavily depends on these decisions makes *