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ee.FeatureCollection.union
使用集合让一切井井有条
根据您的偏好保存内容并对其进行分类。
将指定集合中的所有几何图形合并为一个，并返回一个集合，其中包含一个仅具有“union_result”ID 和一个几何图形的地图项。
| 用法 | 返回 |
|---|
FeatureCollection.union(maxError) | FeatureCollection |
| 参数 | 类型 | 详细信息 |
|---|
此：collection | FeatureCollection | 要合并的集合。 |
maxError | ErrorMargin，默认值：null | 执行任何必要的重新投影时允许的最大误差。如果未指定，则默认为从输出中请求的误差边际。 |
示例
代码编辑器 (JavaScript)
// FeatureCollection of power plants in Belgium.
var fc = ee.FeatureCollection('WRI/GPPD/power_plants')
.filter('country_lg == "Belgium"');
print('Original FeatureCollection', fc);
// Merge all geometries into one. A FeatureCollection with a single feature
// with no properties is returned.
print('All geometries merged into one', fc.union(1));
Python 设置
如需了解 Python API 和如何使用 geemap 进行交互式开发，请参阅
Python 环境页面。
import ee
import geemap.core as geemap
Colab (Python)
# FeatureCollection of power plants in Belgium.
fc = ee.FeatureCollection('WRI/GPPD/power_plants').filter(
'country_lg == "Belgium"')
print('Original FeatureCollection:', fc.getInfo())
# Merge all geometries into one. A FeatureCollection with a single feature
# with no properties is returned.
print('All geometries merged into one:', fc.union(1).getInfo())
如未另行说明，那么本页面中的内容已根据知识共享署名 4.0 许可获得了许可，并且代码示例已根据 Apache 2.0 许可获得了许可。有关详情，请参阅 Google 开发者网站政策。Java 是 Oracle 和/或其关联公司的注册商标。
最后更新时间 (UTC)：2025-07-26。
[null,null,["最后更新时间 (UTC)：2025-07-26。"],[[["\u003cp\u003e\u003ccode\u003eunion()\u003c/code\u003e merges all geometries within a FeatureCollection into a single geometry, returning a new FeatureCollection containing one feature with an ID of 'union_result'.\u003c/p\u003e\n"],["\u003cp\u003eThe resulting FeatureCollection from \u003ccode\u003eunion()\u003c/code\u003e will only have the merged geometry and an ID, discarding any original properties from the input features.\u003c/p\u003e\n"],["\u003cp\u003eAn optional \u003ccode\u003emaxError\u003c/code\u003e argument can be used to specify the maximum allowed error for reprojection during the merge process.\u003c/p\u003e\n"]]],[],null,["# ee.FeatureCollection.union\n\nMerges all geometries in a given collection into one and returns a collection containing a single feature with only an ID of 'union_result' and a geometry.\n\n\u003cbr /\u003e\n\n| Usage | Returns |\n|-----------------------------------------|-------------------|\n| FeatureCollection.union`(`*maxError*`)` | FeatureCollection |\n\n| Argument | Type | Details |\n|--------------------|----------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------|\n| this: `collection` | FeatureCollection | The collection being merged. |\n| `maxError` | ErrorMargin, default: null | The maximum error allowed when performing any necessary reprojections. If not specified, defaults to the error margin requested from the output. |\n\nExamples\n--------\n\n### Code Editor (JavaScript)\n\n```javascript\n// FeatureCollection of power plants in Belgium.\nvar fc = ee.FeatureCollection('WRI/GPPD/power_plants')\n .filter('country_lg == \"Belgium\"');\n\nprint('Original FeatureCollection', fc);\n\n// Merge all geometries into one. A FeatureCollection with a single feature\n// with no properties is returned.\nprint('All geometries merged into one', fc.union(1));\n```\nPython setup\n\nSee the [Python Environment](/earth-engine/guides/python_install) page for information on the Python API and using\n`geemap` for interactive development. \n\n```python\nimport ee\nimport geemap.core as geemap\n```\n\n### Colab (Python)\n\n```python\n# FeatureCollection of power plants in Belgium.\nfc = ee.FeatureCollection('WRI/GPPD/power_plants').filter(\n 'country_lg == \"Belgium\"')\n\nprint('Original FeatureCollection:', fc.getInfo())\n\n# Merge all geometries into one. A FeatureCollection with a single feature\n# with no properties is returned.\nprint('All geometries merged into one:', fc.union(1).getInfo())\n```"]]
