摘要
地图综合是当前国际GIS和制图学领域的一个难题。化简是地图综合的一个基本操作算子,线要素是地图综合操作的主要对象,该文主要研究地图线要素的化简问题。首先,从算法的适用范围、阈值设置等方面分析了现有算法的优点,重点阐述了一种常用的弧比弦算法,并指出了其在化简过程中存在的不足。然后,基于地图曲线的空间认知特征,提出了一种改进弧比弦算法。该算法能够更好地保持曲线的特征点和曲线的几何形态,避免阈值的设置问题。在算法评价上,采用3种定量评价指标,即:偏移平均值、偏移量中值和面积变形值,对改进的弧比弦算法与现有经典算法进行了比较分析。最后,通过算例分析验证了该算法的可行性、有效性和健壮性。
Map generalization is one of hot research themes in the studies of Geographical Information Science and Cartography.Map generalization mainly involve seven basic operators,viz.selection,simplification,aggregation,merging,smoothing,regionalization,and typification.This paper is focused on the simplification of line features.Firstly,the development status of the map generalization is briefly reviewed,and then the most common-used local length ratio algorithm is emphasized,where its advantages and disadvantages are discussed in detail.Next,an improved local length ratio method for curve simplification is proposed.Finally,it is shown by the results of the evaluation test of curve simplification that the proposed algorithm in this paper has a better effect on the curve simplification,the selected nodes can retain the shape of the curve better and noise can be effectively avoided.
出处
《地理与地理信息科学》
CSSCI
CSCD
北大核心
2011年第1期45-48,共4页
Geography and Geo-Information Science
基金
国家自然科学基金项目(40871180)
关键词
地图综合
线要素
化简
map generalization
line feature
simplification
