小编典典

在Python中合并两个GEOJSON多边形

python

有没有办法在python中合并两个重叠的GEOJSON多边形,返回一个合并的GEOJSON对象?


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2021-01-20

共1个答案

小编典典

这就是我如何使用functools中的包/模块json,geojson,shapely,pyproj和partial做到这一点的方法:

import json
import geojson
from functools import partial
import pyproj
import shapely.geometry
import shapely.ops

# reading into two geojson objects, in a GCS (WGS84)
with open('file1.json') as geojson1:
    poly1_geojson = json.load(geojson1)

with open('file2.json') as geojson2:
    poly2_geojson = json.load(geojson2)


# pulling out the polygons
poly1 = shapely.geometry.asShape(poly1_geojson['features'][2]['geometry'])
poly2 = shapely.geometry.asShape(poly2_geojson['features'][2]['geometry'])

# checking to make sure they registered as polygons
print poly1.geom_type
print poly2.geom_type

# merging the polygons - they are feature collections, containing a point, a polyline, and a polygon - I extract the polygon
# for my purposes, they overlap, so merging produces a single polygon rather than a list of polygons
mergedPolygon = poly1.union(poly2)

# using geojson module to convert from WKT back into GeoJSON format
geojson_out = geojson.Feature(geometry=mergedPolygon, properties={})

# outputting the updated geojson file - for mapping/storage in its GCS format
with open('Merged_Polygon.json', 'w') as outfile:
    json.dump(geojson_out.geometry, outfile, indent=3, encoding="utf-8")
outfile.close()

# reprojecting the merged polygon to determine the correct area
# it is a polygon covering much of the US, and dervied form USGS data, so using Albers Equal Area
project = partial(
    pyproj.transform,
    pyproj.Proj(init='epsg:4326'),
    pyproj.Proj(init='epsg:5070'))

mergedPolygon_proj = shapely.ops.transform(project,mergedPolygon)
2021-01-20