GIS中面积偏差控制下的矢量数据压缩算法
作者简介:米学军(1969-),男(回族),山东济阳人,硕士,工程师,主要研究方向为GIS与遥感技术应用。
收稿日期: 2012-03-22
要求修回日期: 2012-07-10
网络出版日期: 2012-10-20
基金资助
中国科学院重大碳专项项目(XDA05060400)资助
A New Algorithm of Vector Date Compression Based On the Tolerance of Area Error in GIS
Received date: 2012-03-22
Request revised date: 2012-07-10
Online published: 2012-10-20
Copyright
米学军 , 盛广铭 , 张 , 婧 , 白焕新 , 侯伟 . GIS中面积偏差控制下的矢量数据压缩算法[J]. 地理科学, 2012 , 32(10) : 1236 -1240 . DOI: 10.13249/j.cnki.sgs.2012.010.1236
:In GIS, vector data is the most commonly used data structure. Data compression is an issue in vector data processing and applications. In this paper,several commonly used algorithms of vector data compression are analyzed and a new efficient algorithm is proposed to resolve the problems of the classic algorithms. The Douglas-Peucker algorithm and the vertical distance tolerance algorithm are commonly used algorithms in vector data compression.The Douglas-Peucker algorithm have the advantage that it has invariance in translation and rotation, but at the same time the result has a big area error and there is a contradiction between the compression ratio and retention of feature points for the curvature change. The advantages of the vertical distance tolerance algorithm is fast, but the area error and the characteristics of the retention curve space are very poor. In this paper,a new algorithm is proposed which improved vertical distance tolerance algorithm and resolved the shortcomings of the Douglas-Peucker algorithm and the vertical distance tolerance algorithm.The basic idea of the new algorithm is based on the vertical distance tolerance algorithm which increase an area error tolerance by adopting the method of straight line fitting to approximate the axis of the polyline in order to resolve the problem of the area error and declination of segment in space. An experiment is included, which verified the new algorithm is efficient by the example of dealing with the boundary contour vector of Chongming Island, Shanghai. In the experiment ,the new algorithm has only 1 km2 error, but the classic algorithms has 6 km2 of the error. The most advantage of the new algorithms is that the area error can be controlled in a specified range. The experiments show that comparing with the two classic algorithms,the new algorithm has no substantial advantage in the compression ratio,but greatly improved the performance of two targets, area error and declination of segment in space. It proved that the new algorithm is efficient in the data procession which has high requirement in area accuracy and spatial characteristics such as the use of land resources.
Fig. 1 Sketch map of the the Douglas-Peucker algorithm图1 道格拉斯-普克算法简化示意图 |
Fig. 2 Sketch map of the vertical distance tolerance algorithm图2 垂直限距算法简化示意图 |
Fig. 3 Sketch map of the declination of segment in space and area error in the classic algorithm图3 线段空间偏移与面积偏差示意图 |
Fig. 4 Results comparison between the classic algorithm and the author′s图4 基于两种不同方法的压缩效果对比 |
Fig. 5 Spatial overlay of among the original data , the classic algorithm and the author′s algorithm results in drawing of partial enlargement图5 两种不同算法的压缩效果与原始数据空间叠加局部放大图 |
Table 1 Area error comparison between the classic algorithm and the author’s表1 垂距限值法与本文算法的面积偏差值对比(m) |
曲线段 | 垂距限值法 | 本文算法 | ||
---|---|---|---|---|
面积偏差 | 空间偏移 | 面积偏差 | 空间偏移 | |
2、3号节点间 | 11.97 | 明显偏移 | 5.0 | 无明显偏移 |
4、5号节点间 | 7.06 | 明显偏移 | 5.0 | 无明显偏移 |
5、6号节点间 | 12.34 | 明显偏移 | 5.0 | 无明显偏移 |
6、7号节点间 | 5.87 | 明显偏移 | 5.0 | 无明显偏移 |
7、8号节点间 | 0.18 | 无明显偏移 | 0.18 | 无明显偏移 |
8、9号节点间 | 4.5 | 无明显偏移 | 4.5 | 无明显偏移 |
10、11号节点间 | 3.45 | 无明显偏移 | 3.45 | 无明显偏移 |
12、13号节点间 | 10.06 | 明显偏移 | 5.0 | 无明显偏移 |
15、16号节点间 | 17.64 | 明显偏移 | 5.0 | 无明显偏移 |
The authors have declared that no competing interests exist.
[1] |
|
[2] |
|
[3] |
|
[4] |
|
[5] |
|
[6] |
|
[7] |
|
[8] |
|
[9] |
|
[10] |
|
[11] |
|
[12] |
|
[13] |
|
[14] |
|
/
〈 |
|
〉 |