公告：所有在
2025 年 4 月 15 日之前注册使用 Earth Engine 的非商业项目都必须
验证是否符合非商业性质的资格条件，才能继续使用 Earth Engine。
ee.FeatureCollection.aggregate_total_var
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。
对集合中对象的指定属性进行汇总，计算所选属性值的总方差。
| 用法 | 返回 |
|---|
FeatureCollection.aggregate_total_var(property) | 数字 |
| 参数 | 类型 | 详细信息 |
|---|
此：collection | FeatureCollection | 要汇总的集合。 |
property | 字符串 | 要从集合的每个元素中使用的属性。 |
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('Total variance of power plant capacities (MW)',
fc.aggregate_total_var('capacitymw')); // 214307.38335169878
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('Total variance of power plant capacities (MW):',
fc.aggregate_total_var('capacitymw').getInfo()) # 214307.38335169878
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\u003eaggregate_total_var\u003c/code\u003e calculates the total variance of a specified property across all features within a FeatureCollection.\u003c/p\u003e\n"],["\u003cp\u003eIt takes the FeatureCollection and the property name as input and returns a numerical value representing the total variance.\u003c/p\u003e\n"],["\u003cp\u003eThis function is useful for understanding the dispersion or spread of a property's values within a dataset.\u003c/p\u003e\n"],["\u003cp\u003eThe example demonstrates calculating the total variance of power plant capacities in Belgium using a publicly available dataset.\u003c/p\u003e\n"]]],["The `aggregate_total_var` function calculates the total variance of a specified property across a FeatureCollection. It takes a FeatureCollection and a property name as input. The function then computes the total variance of the property's values for all objects within the collection. The output is a numerical value representing this total variance. For instance, the example demonstrates calculating the total variance of power plant capacities in Belgium using this method.\n"],null,["# ee.FeatureCollection.aggregate_total_var\n\nAggregates over a given property of the objects in a collection, calculating the total variance of the values of the selected property.\n\n\u003cbr /\u003e\n\n| Usage | Returns |\n|---------------------------------------------------|---------|\n| FeatureCollection.aggregate_total_var`(property)` | Number |\n\n| Argument | Type | Details |\n|--------------------|-------------------|----------------------------------------------------------|\n| this: `collection` | FeatureCollection | The collection to aggregate over. |\n| `property` | String | The property to use from each element of the collection. |\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('Total variance of power plant capacities (MW)',\n fc.aggregate_total_var('capacitymw')); // 214307.38335169878\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('Total variance of power plant capacities (MW):',\n fc.aggregate_total_var('capacitymw').getInfo()) # 214307.38335169878\n```"]]
