检查具有纬度和经度的地理点是否在 shapefile 中

问题描述

如何检查地理点是否在给定 shapefile 的区域内?

How can I check if a geopoint is within the area of a given shapefile?

我设法在 python 中加载了一个 shapefile，但无法继续.

I managed to load a shapefile in python, but can't get any further.

推荐答案

这是对yosukesabai的回答的改编.

This is an adaptation of yosukesabai's answer.

我想确保我正在搜索的点与 shapefile 在同一个投影系统中，因此我为此添加了代码.

I wanted to ensure that the point I was searching for was in the same projection system as the shapefile, so I've added code for that.

我不明白他为什么要对 ply = feat_in.GetGeometryRef() 进行包含测试(在我的测试中，没有它似乎也能正常工作)，所以我删除了它.

I couldn't understand why he was doing a contains test on ply = feat_in.GetGeometryRef() (in my testing things seemed to work just as well without it), so I removed that.

我还改进了评论以更好地解释正在发生的事情(据我了解).

I've also improved the commenting to better explain what's going on (as I understand it).

#!/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)

这个网站, 这个网站，和 这个网站对投影检查很有帮助.EPSG:4326

This site, this site, and this site were helpful regarding the projection check. EPSG:4326

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