The Research And Application Of The Feature Labeling In Electronic Map

GIS (Geographic Information System) is a new rising subject which is the combination of the computer science, information science, geography, mapping, environment science, space science, geology, and manage science. It is an architectonic aggregate of computer software and hardware. It can efficiently create,operate,analyze and display manifold data of geography or space reference, combine with graphics and data, express the data information of geography graphics enough.Along with the using of GIS widely, some basic problems in map display become more and more important and people pay more and more attention to them ,such as label placement, for in no matter what field , the quality of the map display can affect the quality of the software directly.Label problem of map is one of the most basic and important research questions in GIS. This question has already been recognized as an important question for the research area of separate computing geometry. In GIS, three different label-placement tasks are usually identified: labeling of point features (such as cities or mountain peaks), line features (such as rivers or roads), and area features (such as oceans or countries).Map labeling can enhance our intelligibility for map in the very great degree. Therefore, the algorithm of map labeling and the performance is always the foundation question of charting and GIS. How can we find the best position collection of label for map, which is the problem that people are always discussing.This article that bases on the existing questions and theory of map labeling, I have summarized the problems, giving the supplement and the improvement to the question which exists in GIS labeling algorithm. For the point features labeling, I use algorithm which easy to realize and the rate of running of it is quick, and I apply algorithm that can obtain the good quality labeling result in this article. For the line features labeling, proposing one kind of new algorithm which is classified processing algorithm to linear feature labeling. And it will adopt the backtracking technique to solve the conflict which produces in the linear feature labeling. For the area features labeling, firstly, this article adopts classified processing algorithm to area features labeling, making the improvement to the skeletons of the area polygons, it can satisfy the effect of the labeling as well as the speed of the labeling that in the area features labeling. I have realized the algorithm of the point features labeling, the algorithm of the line features labeling, the algorithm of the area features labeling under the VB6.0+MapX5.0 programming environment, and apply the three kinds of algorithm of labeling to the software which I have developed. Experiment has proved: using labeling algorithm of this article that apply to the concrete example, it can obtain the good effect.