a) (b) Figure 1: Wheelchair accessible stations in Prague metro. (a) Octilinear and (b) orthogonal annotated maps. AbstractAnnotating metro maps with thumbnail photographs is a commonly used technique for guiding travelers. However, conventional methods usually suffer from small labeling space around the metro stations, especially when they are interchange stations served by two or more metro lines. This paper presents an approach for aesthetically designing schematic metro maps while ensuring effective placement of large annotation labels that are sufficiently close to their corresponding stations. Our idea is to distribute such labels in a well-balanced manner to labeling regions around the metro network first and then adjust the lengths of metro line and leader line segments, which allows us to fully maximize the space coverage of the entire annotated map. This is accomplished by incorporating additional constraints into the conventional mixed-integer programming formulation, while we devised a three-step algorithm for accelerating the overall optimization process. We include several design examples to demonstrate the spatial efficiency of the map layout generated using the proposed approach through minimal user intervention.

Figure 1: Side-by-side comparison between an ordinary perspective view (left) and its optimally distorted version with our approach (right). Note that we can successfully avoid the occlusions of important route to the destination (drawn in orange) while accentuating the 3D appearance of the landmark buildings. ( ABSTRACTIn composing hand-drawn 3D urban maps, the most common design problem is to avoid overlaps between geographic features such as roads and buildings by displacing them consistently over the map domain. Nonetheless, automating this map design process is still a challenging task because we have to maximally retain the 3D depth perception inherent in pairs of parallel lines embedded in the original layout of such geographic features. This paper presents a novel approach to disoccluding important geographic features when creating 3D urban maps for enhancing their visual readability. This is accomplished by formulating the design criteria as a constrained optimization problem based on the linear programming approach. Our mathematical formulation allows us to systematically eliminate occlusions of landmark roads and buildings, and further controls the degree of local 3D map deformation by devising an objective function to be minimized. Various design examples together with a user study are presented to demonstrate the robustness and feasibility of the proposed approach.