2013-03-06 141 views
0

我在Python中使用OGR距离来确定点和线之间的最短距离。我的结果与使用QGIS的结果完全不同。我假设OGR使用的单位取决于坐标系? OGR是否使用学位?如果是的话,我怎么能把它们转换成米? 我的代码如下所示:OGR距离单位

import ogr 

driver = ogr.GetDriverByName('ESRI Shapefile') 

roads = driver.Open('G:/Basedata/OR/infra/TigerRoads2010/OR_TIGERroads_2010_merge.shp', 0) 
point = driver.Open('U:/My Documents/Tool/shp/testareacentro.shp', 0) 

roadslayer = roads.GetLayer() 
pointl = point.GetLayer() 

roadsfeature = roadslayer.GetNextFeature() 
pointf = pointl.GetNextFeature() 

roadgeom = roadsfeature.GetGeometryRef() 
pointgeom = pointf.GetGeometryRef() 

dist = pointgeom.Distance(roadgeom) 

print dist 
+1

我期望的单位是输入的单位。 – askewchan 2013-03-06 19:55:58

+0

如何找出输入的单位是什么? – ustroetz 2013-03-06 19:58:37

+0

你必须看看输入来自哪里。如果你给一个点作为元组,这些数字代表什么? – askewchan 2013-03-06 20:01:54

回答

0

之所以我的距离是关闭的,是因为我只比第一个特征。 这将代码可以得到同样的结果在QGIS:

import ogr 

driver = ogr.GetDriverByName('ESRI Shapefile') 

lineshp = driver.Open('U:/My Documents/Tool/shp/line.shp', 0) 
linelyr = lineshp.GetLayer() 

pointshp = driver.Open('U:/My Documents/Tool/shp/point.shp', 0) 
pointlyr = pointshp.GetLayer() 

linefeat = linelyr.GetNextFeature() 
pointfeat = pointlyr.GetNextFeature() 

point_geom = pointfeat.GetGeometryRef() 

distlist = [] 
while linefeat: 
    line_geom = linefeat.GetGeometryRef() 
    dist = point_geom.Distance(line_geom) 
    distlist.append(dist) 
    linefeat.Destroy() 
    linefeat = linelyr.GetNextFeature() 

print min(distlist)