| There are revolutionary changes in the field of cartography with the development of computer technology. Cartography has change from traditional manual mapping into digital mapping. Previous people make maps through manual production, and the production cycle is long, the map is low precision. As accumulate a large number of maps in digital data today, people can produce maps through digital data in database. But how long we can make a map through digital data in database? We hope the computer can make a map automatically through digital data in database. So it can make maps quickly. That Computer can make a map automatically is the focus of research in cartography. The cartographic label placement automation problem is an important segment in it, which is also a challenging topic in cartography.The most important issue is overlapping between the labels of cartographic element on cartographic label placement. As it called label conflicts. Label conflicts have destroyed the clarity and completeness. And make labels could not serve to transmit information. And also affect the overall appearance of the map. Furthermore, overlap between labels and elements. As it called label overlap. Labels overlap with the elements is unavoidable, but some important elements or important characteristic location of elements are not allowed to be overlapped. The essence of the cartographic label placement is an optimization problem. And its most immediate problem is to solve the conflict between the labels. This article includes the following aspects:1, Systematic analysis the relationship between labels and the elements with which label placed. And describe the classification of cartographic label, the function of labels, the design of labels, and pattern of labels.2, Summarized the two models of point features label placement and three models of the result of point feature label placement (or called solution). And put forward a concept of adjacency relations of labels based the conflict graph of labels. Finally generate the adjacency list of the point feature label, and using it to place the label of point feature. 3, Ant colony algorithm have introduced in the problem of point feature label intelligent placement. And design an ant colony algorithm with the point feature label placement, and prove the feasibility by experiment.4, Also design a hybrid genetic algorithm with the point feature label placement. The algorithm is hybridized a greedy algorithm with genetic algorithm. Then test 4 different crossover operators of the hybrid genetic algorithm by experiment.5, Introduced the Imhof’s rules of linear positioning label on map. Also introduced a linear label placement program which can fulfill the curvature constrains by the Imhof’s rules.6, Area feature label placement had simplified into 4 classes. For large area feature, the skeleton is a candidate of label placement. Therefore summarize several methods with generated skeleton in vector and raster mode. To decide the Shape Features of polygon make an idea by some indicators which named Form Ratic, Circularity Ratio and Compactness Ratio. |
