ee.String.evaluate

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
String.evaluate(callback)
参数类型详细信息
此：computedobjectComputedObjectComputedObject 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.String object fetched from a feature property.
var stringServer = ee.Feature(null, {lc: 'grassland'}).getString('lc');

// Use evaluate to transfer server-side string to client for use in ui.Label.
stringServer.evaluate(function(stringClient) {
  print('Client-side primitive data type', typeof stringClient);  // string
  print('Client-side string', stringClient);  // grassland
  print('Client-side string used in ui.Label',
        ui.Label('Land cover: ' + stringClient));  // Land cover: grassland
});

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.String objects.
# Use ee.String.getInfo() instead.