OGR距离单位

Question

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：

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 

Answer 1

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)