Research on Map Labeling Problems in Geographic Information System

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The automatic placement of text or symbol labels corresponding to graphical features in two dimensional maps is important in several application areas. In maps, labels (or names) of regions, rivers and stations, etc., are placed in appropriate positions understood. Where to place such labels is important for readability of a map. The problem of placing such labels is called the map labeling problem. The aim of this research project is to develop efficient algorithms for the problem, and we also investigate topics having connection with this problem.There are two types for the labeling problem. One of them is the label number maximization problem, and the other is the label size maximization problem. First, we considered the label number maximization problem for labeling points and curves in maps drawn from digital data. In discrete models, we have to manage many candidate positions and cannot adjust label positions by fine amounts. Therefore, we used continuous labeling spaces for points and curves, and proposed efficient algorithms. However, as many points may be distributed densely, the labeling space for a point could be empty. We know that it is impossible to place all the points in this case. One approach to this problem is placing labels using leader lines. We formulate the model with leader lines. Some practical algorithms are proposed in this project and computational results are also shown. For the label size maximization problem, we can develop efficient algorithms, too.When we consider the application of this problem to Intelligent Transport System, we have to maintain dynamic change of geometric data, and we investigate such cases.~ Moreover, there are many problems having strong connection with the labeling problem in application areas, we also consider those problems.