Ti, Wu, Li Z , Li M, Dai and Xiong – EVEALING SCHEMATIC MAP DESIGNS WITH PRESERVATION OF RELATIVITY IN NODE POSITION AND SEGMENT LENGTH IN EXISTING OFFICIAL MAPS 2023

Description

This empirical study analyzes how manual designers preserve two “principle of relativity” relations—relative node position and relative segment length—when creating schematic transit maps. Using 32 official underground maps (922 nodes, 1,294 segments), the authors define quantitative measures for local, medium (half), and global preservation and compute preservation ratios. Designers largely preserve relative relations (mean ≈88% for positions, ≈83% for lengths), with global preservation significantly higher than local. When dense central regions are enlarged, relative position is prioritized over relative length. The authors hypothesize designers reduce complexity by anchoring preservation to reference objects (e.g., central regions or major axes), explaining regional differences and suggesting a strategy to relax constraints in automated schematization. Recommendations include treating relative position as higher priority and leveraging reference axes or regions to improve computational efficiency and clarity. Limitations include focusing only on nodes and segments; future work should add stations, landmarks, and user-cognition studies. The appendix documents source maps (mostly Chinese, some international), data/code links, funding, and full references.