Shape Decision-Making in Map-Like Visualization Design Using the Simulated Annealing Algorithm

Semantic information without spatial characteristics can also be visualised in the form of a map. This map type is usually called map-like visualisation; it is not a representation of a real geo-entity but borrows the map metaphor. In current map-like visualisation works, the manipulation of the cartographic process is poor, and there is a considerable amount of randomness and uncertainty in the map results. For instance, in the process of converting semantic objects to map objects, the map shape is usually uncertain and has many possibilities. Frequently, however, we need shapes to follow certain principles, such as the principles of being close to a certain shape and having a simple geometry, to facilitate recognition and mapping. To achieve a balance between uncertain shapes and design needs, this study enhances the realisation of the cartographer's design idea by improving the controllability in the cartographic process. An optimisation technology, the simulated annealing algorithm, is introduced to control the determination of shape to improve mapping efficiency. Experiments based on real data show that based on this method, the map-like representation not only creates a whole outline close to the pre-defined shape but also realises internal regions with a simple shape.