ee.Dictionary.evaluate

  • The Dictionary.evaluate method asynchronously retrieves the value of a dictionary object from the server and passes it to a callback function.

  • The callback function is executed when the server returns an answer, with the success argument containing the evaluated result on success and the failure argument containing an error message on failure.

  • In JavaScript, dictServer.evaluate can be used to transfer a server-side dictionary to the client for client-side operations.

  • The Earth Engine Python client library does not have an evaluate method for asynchronous evaluation; instead, ee.Dictionary.getInfo() should be used.

Asynchronously retrieves the value of this object from the server and passes it to the provided callback function.

UsageReturns
Dictionary.evaluate(callback)
ArgumentTypeDetails
this: computedobjectComputedObjectThe ComputedObject instance.
callbackFunctionA 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.

Examples

Code Editor (JavaScript)

// A dictionary (e.g. results of ee.Image.reduceRegion of an S2 image).
var dictServer = ee.Dictionary({
  B1: 182,
  B2: 219,
  B3: 443
});

// Use evaluate to transfer server-side dictionary to the client.
dictServer.evaluate(function(dictClient) {
  print('Client-side dot notation to access "B1" value', dictClient.B1);
  print('Client-side bracket notation to access "B1" value', dictClient['B1']);

  print('Client-side operations to print all key-value pairs');
  Object.keys(dictClient).forEach(function(key) {
    print('    ' + key + ': ' + dictClient[key]);
  });
});

Python setup

See the Python Environment page for information on the Python API and using geemap for interactive development.

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