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ee.Geometry.evaluate
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。
以异步方式从服务器检索此对象的值,并将其传递给所提供的回调函数。
用法 | 返回 |
---|
Geometry.evaluate(callback) | |
参数 | 类型 | 详细信息 |
---|
此:computedobject | ComputedObject | ComputedObject 实例。 |
callback | 函数 | 一种函数,形式为 function(success, failure),在服务器返回答案时调用。如果请求成功,success 实参将包含评估结果。如果请求失败,失败实参将包含错误消息。 |
示例
代码编辑器 (JavaScript)
// Define a callback function that prints a GeoJSON string.
var printGeoJSONString = function(geometry) {
geometry = ee.Geometry(geometry);
print(geometry.toGeoJSONString());
};
// Create a simple computed geometry.
var computedGeometry = ee.Geometry.Point(0, 0).buffer(10);
// Evaluate the callback function that asynchronously retrieves and prints
// the GeoJSON string representation of computed geometry.
computedGeometry.evaluate(printGeoJSONString);
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)
# The Earth Engine Python client library does not have an evaluate method for
# asynchronous evaluation of ee.Geometry objects.
# Use ee.Geometry.getInfo() instead.
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\u003eGeometry.evaluate\u003c/code\u003e is a method used to asynchronously retrieve the value of a ComputedObject (like a Geometry) from the server.\u003c/p\u003e\n"],["\u003cp\u003eIt takes a callback function as an argument, which is executed upon receiving the server response, providing either the evaluated result or an error message.\u003c/p\u003e\n"],["\u003cp\u003eThe example demonstrates using \u003ccode\u003eGeometry.evaluate\u003c/code\u003e with a callback function to print the GeoJSON representation of a computed geometry.\u003c/p\u003e\n"],["\u003cp\u003eWhile the JavaScript example showcases \u003ccode\u003eGeometry.evaluate\u003c/code\u003e, the Python library uses \u003ccode\u003eGeometry.getInfo()\u003c/code\u003e for similar functionality.\u003c/p\u003e\n"]]],["The `evaluate` method asynchronously retrieves a `ComputedObject`'s value from the server and provides it to a callback function. The callback receives a success or failure argument, with the result or error message, respectively. The example in javascript shows how it is used with a `GeoJSON` string to display the result. In python, there is not an `evaluate` method, instead you have to use the `getInfo()` method.\n"],null,["# ee.Geometry.evaluate\n\n\u003cbr /\u003e\n\nAsynchronously retrieves the value of this object from the server and passes it to the provided callback function.\n\n\u003cbr /\u003e\n\n| Usage | Returns |\n|-------------------------------|---------|\n| Geometry.evaluate`(callback)` | |\n\n| Argument | Type | Details |\n|------------------------|----------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|\n| this: `computedobject` | ComputedObject | The ComputedObject instance. |\n| `callback` | Function | A function of the form function(success, failure), called when the server returns an answer. If the request succeeded, the success argument contains the evaluated result. If the request failed, the failure argument will contains an error message. |\n\nExamples\n--------\n\n### Code Editor (JavaScript)\n\n```javascript\n// Define a callback function that prints a GeoJSON string.\nvar printGeoJSONString = function(geometry) {\n geometry = ee.Geometry(geometry);\n print(geometry.toGeoJSONString());\n};\n\n// Create a simple computed geometry.\nvar computedGeometry = ee.Geometry.Point(0, 0).buffer(10);\n\n// Evaluate the callback function that asynchronously retrieves and prints\n// the GeoJSON string representation of computed geometry.\ncomputedGeometry.evaluate(printGeoJSONString);\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# The Earth Engine Python client library does not have an evaluate method for\n# asynchronous evaluation of ee.Geometry objects.\n# Use ee.Geometry.getInfo() instead.\n```"]]