Research On Line-Simplification Algorithm In Scaleless GIS

Line generalization, one of the most important fields of the cartographic generalization, is still a central issue for experts and scholars after many years'development. That has two reasons: one is the importance of line in map representation, the other is the imperfectability and immaturity of the theory of cartographic generalization and line generalization itself. In addition, as a main partition of spatial imformation representation, analysis and deal of line play an important role in GIS. With the expansion of GIS appling field and development of Internet technique, now aviliable data processing system of GIS couldn't meet the requirements of the information society. One of the important reasons is that GIS couldn't adjust the quantity of spatial information with deriving small scale from large scale automatically, which is also called spatial information compression and reappearance of scaleless GIS. Consequently, it's essential to pay attentions to the research in line simplification more than in line generazalation.This paper focuses on line-simplification algorithms in scaleless GIS as well as algorithms implementation, and designs and establishes a line-simplification system. The principal contents in this thesis are as follows: Studying status and researching meaning in terms of multi-scale GIS, multiple representation database, scaleless GIS and automatic cartographic generalization. Introducing basic algorithms of line-simplification, especially the Douglas-Peucker algorithm. The Queue and Stack data structure is put forward to realize the Douglas-Peucker algorithm for improving the efficiency, and the selecting of threshold and binary tree structure that builds in this algorithm are considered and analysized thoroughly as well as its application in sacleless GIS. Analysizing the reason that why line-simplification algorithm can...