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.Date.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 |
---|
Date.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)
/**
* WARNING: this function transfers data from Earth Engine servers to the
* client. Doing so can negatively affect request processing and client
* performance. Server-side options should be used whenever possible.
* Learn more about the distinction between server and client:
* https://developers.google.com/earth-engine/guides/client_server
*/
// A server-side ee.Date object.
var dateServer = ee.Date('2021-4-30');
// Use evaluate to transfer server-side date to the client. The result is
// an object with keys "type" and "value" where "value" is milliseconds since
// Unix epoch.
dateServer.evaluate(function(dateClient) {
print('Client-side date is an object', typeof dateClient);
print('Object keys include "type" and "value"', Object.keys(dateClient));
print('"value" is milliseconds since Unix epoch', dateClient.value);
print('Client-side date in JS Date constructor', new Date(dateClient.value));
});
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.Date objects.
# Use ee.Date.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。"],[],["The `Date.evaluate(callback)` method asynchronously retrieves a ComputedObject's value from the server. It uses a callback function with `success` and `failure` arguments to handle the server's response. If successful, `success` provides the evaluated result; otherwise, `failure` gives an error message. The JavaScript example transfers a server-side date to the client, revealing its \"type\" and \"value\" (milliseconds since Unix epoch). Python uses `ee.Date.getInfo()` for similar functionality.\n"],null,[]]