基于结构分析的曲线概括方法

Line Generalization Based on Structure Analysis

线状要素往往是地图的主要构成要素，因此在概括过程中常常需要进行对曲线进行概括处理．目前已存在的曲线概括方法主要是一种几何上的逼近，概括处理后难以保持其原有形态特点．以曲线形态分析为基础，提出基于复合弯曲分析的曲线概括方法．

Line generalization is an important issue receiving extensive attention in the field of map generalization. In the past 30 years, numbers of algorithms were designed for line generalization. Most of those algorithms are based on distance, area and other parameters, which result in generalized lines approximating the original lines geometi -cally. The generalized lines usually lost their original shape in some way. In order to maintain the shape of original lines, lines can he divided into structural units. Among all possible structural units, compound bend is a reasonable one for line division. Based on compound bend analysis, methods for line generalization are designed, including bend deletion, combination and exaggeration. These three generalization operators are iteratively processed so that samll basic bends are replaced by compound bends larger than threshold. A case study is carried out to test the method, and some examples show that satisfactory results can be obtained by this method.