Haverkort and Miermans – A PURELY FORCE-DIRECTED APPROACH TO DRAWING METRO MAPS WITH CURVES 2014

Description

Haverkort and Miermans present a new force-directed method for automatically drawing smooth, curved metro maps. Unlike prior work that sometimes replaces long segments by single Bézier curves, their approach represents every segment between consecutive stations with a quadratic Bézier curve and defines forces on the curve parameters. Forces include repulsion between stations to avoid crowding, attraction along lines to distribute stations uniformly, straightening forces on control points, smoothing forces that average curvature over about seven stops each direction, orienting forces to preserve compass direction, and fitting forces to respect map aspect ratio. They omit forces that tether stations to original geographic positions to allow greater schematic freedom. Preliminary results on the Madrid metro produce smooth, space-efficient drawings in minutes; missing repulsive inter-line forces cause some artifacts. Future work includes improving topographic accuracy, preserving relative distances where needed, stricter orientation at interchanges, preventing spurious crossings, and accommodating labels.