Evaluation model for map labeling of urban rail transit schematic map

A quality evaluation model is given out for automatic label placement concentrating on urban rail transit schematic (URTS) maps with analytic hierarchy process (AHP) method. Besides independent elements of legibility threshold, label-feature overlap, position optimal level and label-feature association, we propose two compensatory indicators that related to the number of labels per unit and distortion level for the comparison of label quality among different URTS maps. The rail transit schematic maps of Shanghai, London, Moscow, Milan, Sao Paulo are presented as example verification. The result shows that the two compensatory indicators are reasonable.