在Python

Question

我有一个包含一系列代表县的多边形的shapefile。 我想知道Python中的一个函数/模块，它可以在给定单点坐标的情况下导出'边界'多边形。

换句话说，一个函数使用一个点的lat / lon坐标和shapefile，并返回包含该点的shapefile中的多边形。见图：

正如您所看到的，该点位于“蓝色”多边形内，这是我对任何给定点所需要的。

我知道可能没有内置功能可以做到这一点，但任何关于如何解决这个问题的建议都会非常好，谢谢！

Answer 1

理查德对类似问题的回答是最好的。

在此处找到：https://stackoverflow.com/a/13433127/7019148

复制如下以供将来参考：

#!/usr/bin/python
import ogr
from IPython import embed
import sys

drv = ogr.GetDriverByName('ESRI Shapefile') #We will load a shape file
ds_in = drv.Open("MN.shp")    #Get the contents of the shape file
lyr_in = ds_in.GetLayer(0)    #Get the shape file's first layer

#Put the title of the field you are interested in here
idx_reg = lyr_in.GetLayerDefn().GetFieldIndex("P_Loc_Nm")

#If the latitude/longitude we're going to use is not in the projection
#of the shapefile, then we will get erroneous results.
#The following assumes that the latitude longitude is in WGS84
#This is identified by the number "4326", as in "EPSG:4326"
#We will create a transformation between this and the shapefile's
#project, whatever it may be
geo_ref = lyr_in.GetSpatialRef()
point_ref=ogr.osr.SpatialReference()
point_ref.ImportFromEPSG(4326)
ctran=ogr.osr.CoordinateTransformation(point_ref,geo_ref)

def check(lon, lat):
    #Transform incoming longitude/latitude to the shapefile's projection
    [lon,lat,z]=ctran.TransformPoint(lon,lat)

    #Create a point
    pt = ogr.Geometry(ogr.wkbPoint)
    pt.SetPoint_2D(0, lon, lat)

    #Set up a spatial filter such that the only features we see when we
    #loop through "lyr_in" are those which overlap the point defined above
    lyr_in.SetSpatialFilter(pt)

    #Loop through the overlapped features and display the field of interest
    for feat_in in lyr_in:
        print lon, lat, feat_in.GetFieldAsString(idx_reg)

#Take command-line input and do all this
check(float(sys.argv[1]),float(sys.argv[2]))
#check(-95,47)