如何使用 python 从 geojson 创建 GeometryCollection？
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【中文标题】如何使用 python 从 geojson 创建 GeometryCollection？【英文标题】：How to create GeometryCollection from geojson with python shapely? 【发布时间】：2017-04-01 01:15:09 【问题描述】：我想计算几何的面积，其中一些几何可以是几何集合。但我不能这样做，因为 shapely 不会从 geojson 创建几何集合。
这里是示例代码：
import sys
import shapely
from shapely.geometry import shape
print sys.version
print shapely.__version__
shp = shape( "type" : "GeometryCollection", "geometries" : [ "type" : "MultiPolygon", "coordinates" : [ [ [ [ -176.392059198913, -44.2871679740063 ], [ -176.392051742896, -44.287151383102 ], [ -176.392031530803, -44.2871344706636 ], [ -176.39200961191, -44.2871265610425 ], [ -176.391981764136, -44.2871247604782 ], [ -176.391958318107, -44.2871296477241 ], [ -176.391938555171, -44.2871399366613 ], [ -176.391926697409, -44.2871518332429 ], [ -176.391919510887, -44.2871685527587 ], [ -176.391919510887, -44.2871809637809 ], [ -176.391926697409, -44.2871977475943 ], [ -176.39194142978, -44.2872117662547 ], [ -176.391952299394, -44.2872176823855 ], [ -176.391975026771, -44.2872241772677 ], [ -176.392002874545, -44.287224370185 ], [ -176.392025601922, -44.2872180682202 ], [ -176.392043837722, -44.2872068790156 ], [ -176.392055875147, -44.2871915742382 ], [ -176.392059198913, -44.2871679740063 ] ] ], [ [ [ -176.395054990554, -44.2866718524961 ], [ -176.394985011794, -44.2865985431944 ], [ -176.394870296932, -44.2865318573729 ], [ -176.39471973929, -44.2864943666608 ], [ -176.394478451805, -44.2864536605947 ], [ -176.394252974669, -44.2864997684115 ], [ -176.39423896095, -44.2864981607477 ], [ -176.394288098796, -44.2862575894326 ], [ -176.394110412033, -44.2860409393617 ], [ -176.393535220757, -44.2860305859249 ], [ -176.393376668109, -44.2861752766473 ], [ -176.393372446027, -44.2862439563855 ], [ -176.39308166137, -44.2869353793885 ], [ -176.39289184735, -44.2873133692894 ], [ -176.39283543315, -44.2873595407371 ], [ -176.392827258481, -44.2874577353246 ], [ -176.393011952104, -44.2875944486682 ], [ -176.393422751683, -44.2876439637706 ], [ -176.393631699818, -44.2875120734508 ], [ -176.393639694824, -44.2875105944256 ], [ -176.393681556316, -44.2875372811799 ], [ -176.39377641841, -44.287580044267 ], [ -176.393856817628, -44.2876262798103 ], [ -176.393945122021, -44.2877477524342 ], [ -176.393972790132, -44.2878800923601 ], [ -176.394000817568, -44.2880426552818 ], [ -176.394041062093, -44.2881004653263 ], [ -176.394137451323, -44.2881293381748 ], [ -176.39437882864, -44.2881469576789 ], [ -176.39444934639, -44.288034231344 ], [ -176.394488512936, -44.2878805424954 ], [ -176.39452749982, -44.2877896794012 ], [ -176.394566756197, -44.2876918712001 ], [ -176.394586429302, -44.2875450621349 ], [ -176.394533159206, -44.2873842340869 ], [ -176.394460844825, -44.2872859750708 ], [ -176.394428864801, -44.2872049498422 ], [ -176.394396705114, -44.2871413513901 ], [ -176.39438879994, -44.2870604545739 ], [ -176.394445393803, -44.2869391734468 ], [ -176.394558042539, -44.2869161518684 ], [ -176.394670691276, -44.2869161518684 ], [ -176.394839754212, -44.286887471342 ], [ -176.394996330566, -44.2868534533899 ], [ -176.39503531745, -44.2868046449896 ], [ -176.395045109086, -44.2867417534732 ], [ -176.395054990554, -44.2866718524961 ] ] ] ] , "type" : "MultiLineString", "coordinates" : [ [ [ -176.394252974669, -44.2864997684115 ], [ -176.394075737063, -44.2866440721399 ] ], [ [ -176.394075737063, -44.2866440721399 ], [ -176.39390685379, -44.2866785403577 ] ], [ [ -176.39390685379, -44.2866785403577 ], [ -176.393761955534, -44.286695774459 ] ], [ [ -176.393761955534, -44.286695774459 ], [ -176.393633137123, -44.2867187318175 ] ], [ [ -176.393633137123, -44.2867187318175 ], [ -176.393624872622, -44.2868689511739 ] ], [ [ -176.393624872622, -44.2868689511739 ], [ -176.393624962454, -44.286990361058 ] ], [ [ -176.393624962454, -44.286990361058 ], [ -176.393624513296, -44.2870655347429 ] ], [ [ -176.393624513296, -44.2870655347429 ], [ -176.393624423464, -44.2871117706912 ] ], [ [ -176.393624423464, -44.2871117706912 ], [ -176.393615889469, -44.2873486730876 ] ], [ [ -176.393615889469, -44.2873486730876 ], [ -176.393639694824, -44.2875105944256 ] ] ] ] )
print shp.area
这是输出：
2.7.6 (default, Jun 22 2015, 17:58:13)
[GCC 4.8.2]
1.5.13
Traceback (most recent call last):
...
File "/usr/local/lib/python2.7/dist-packages/Shapely-1.5.13-py2.7.egg/shapely/geometry/geo.py", line 42, in shape
raise ValueError("Unknown geometry type: %s" % geom_type)
ValueError: Unknown geometry type: geometrycollection
也许最新版本的 shapely 可以做到这一点？如果是这样，我可以在 ubuntu 下安装什么版本？如果没有，计算几何收集区域的替代方法是什么？
【问题讨论】：
【参考方案1】：从 Shapely 1.6b2 开始，这可以使用您正在使用的确切命令！
【讨论】：
【参考方案2】：我不知道shapely 处理这样的混合类型（尽管我可能是错的）。我认为您需要利用对 geojson 结构的理解来正确提取您要查找的信息。例如，您可以在几何集合中选择与多边形对应的坐标，然后将它们转换为shapely 多边形，如下所示：
geo_dict = "type" : "GeometryCollection", "geometries" : [ "type" : "MultiPolygon", "coordinates" : [ [ [ [ -176.392059198913, -44.2871679740063 ], [ -176.392051742896, -44.287151383102 ], [ -176.392031530803, -44.2871344706636 ], [ -176.39200961191, -44.2871265610425 ], [ -176.391981764136, -44.2871247604782 ], [ -176.391958318107, -44.2871296477241 ], [ -176.391938555171, -44.2871399366613 ], [ -176.391926697409, -44.2871518332429 ], [ -176.391919510887, -44.2871685527587 ], [ -176.391919510887, -44.2871809637809 ], [ -176.391926697409, -44.2871977475943 ], [ -176.39194142978, -44.2872117662547 ], [ -176.391952299394, -44.2872176823855 ], [ -176.391975026771, -44.2872241772677 ], [ -176.392002874545, -44.287224370185 ], [ -176.392025601922, -44.2872180682202 ], [ -176.392043837722, -44.2872068790156 ], [ -176.392055875147, -44.2871915742382 ], [ -176.392059198913, -44.2871679740063 ] ] ], [ [ [ -176.395054990554, -44.2866718524961 ], [ -176.394985011794, -44.2865985431944 ], [ -176.394870296932, -44.2865318573729 ], [ -176.39471973929, -44.2864943666608 ], [ -176.394478451805, -44.2864536605947 ], [ -176.394252974669, -44.2864997684115 ], [ -176.39423896095, -44.2864981607477 ], [ -176.394288098796, -44.2862575894326 ], [ -176.394110412033, -44.2860409393617 ], [ -176.393535220757, -44.2860305859249 ], [ -176.393376668109, -44.2861752766473 ], [ -176.393372446027, -44.2862439563855 ], [ -176.39308166137, -44.2869353793885 ], [ -176.39289184735, -44.2873133692894 ], [ -176.39283543315, -44.2873595407371 ], [ -176.392827258481, -44.2874577353246 ], [ -176.393011952104, -44.2875944486682 ], [ -176.393422751683, -44.2876439637706 ], [ -176.393631699818, -44.2875120734508 ], [ -176.393639694824, -44.2875105944256 ], [ -176.393681556316, -44.2875372811799 ], [ -176.39377641841, -44.287580044267 ], [ -176.393856817628, -44.2876262798103 ], [ -176.393945122021, -44.2877477524342 ], [ -176.393972790132, -44.2878800923601 ], [ -176.394000817568, -44.2880426552818 ], [ -176.394041062093, -44.2881004653263 ], [ -176.394137451323, -44.2881293381748 ], [ -176.39437882864, -44.2881469576789 ], [ -176.39444934639, -44.288034231344 ], [ -176.394488512936, -44.2878805424954 ], [ -176.39452749982, -44.2877896794012 ], [ -176.394566756197, -44.2876918712001 ], [ -176.394586429302, -44.2875450621349 ], [ -176.394533159206, -44.2873842340869 ], [ -176.394460844825, -44.2872859750708 ], [ -176.394428864801, -44.2872049498422 ], [ -176.394396705114, -44.2871413513901 ], [ -176.39438879994, -44.2870604545739 ], [ -176.394445393803, -44.2869391734468 ], [ -176.394558042539, -44.2869161518684 ], [ -176.394670691276, -44.2869161518684 ], [ -176.394839754212, -44.286887471342 ], [ -176.394996330566, -44.2868534533899 ], [ -176.39503531745, -44.2868046449896 ], [ -176.395045109086, -44.2867417534732 ], [ -176.395054990554, -44.2866718524961 ] ] ] ] , "type" : "MultiLineString", "coordinates" : [ [ [ -176.394252974669, -44.2864997684115 ], [ -176.394075737063, -44.2866440721399 ] ], [ [ -176.394075737063, -44.2866440721399 ], [ -176.39390685379, -44.2866785403577 ] ], [ [ -176.39390685379, -44.2866785403577 ], [ -176.393761955534, -44.286695774459 ] ], [ [ -176.393761955534, -44.286695774459 ], [ -176.393633137123, -44.2867187318175 ] ], [ [ -176.393633137123, -44.2867187318175 ], [ -176.393624872622, -44.2868689511739 ] ], [ [ -176.393624872622, -44.2868689511739 ], [ -176.393624962454, -44.286990361058 ] ], [ [ -176.393624962454, -44.286990361058 ], [ -176.393624513296, -44.2870655347429 ] ], [ [ -176.393624513296, -44.2870655347429 ], [ -176.393624423464, -44.2871117706912 ] ], [ [ -176.393624423464, -44.2871117706912 ], [ -176.393615889469, -44.2873486730876 ] ], [ [ -176.393615889469, -44.2873486730876 ], [ -176.393639694824, -44.2875105944256 ] ] ] ] # the contents of your geojson, as above
geometries = geo_dict["geometries"]
polygon_bounds = [geom['coordinates'] for geom in geometries if "Polygon" in geom["type"]]
polygons = [shapely.geometry.Polygon(b[0]) for b in polygon_bounds[0]]
areas = [p.area for p in polygons]
【讨论】：
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