ee.Date.evaluate
קל לארגן דפים בעזרת אוספים
אפשר לשמור ולסווג תוכן על סמך ההעדפות שלך.
הפונקציה מאחזרת באופן אסינכרוני את הערך של האובייקט הזה מהשרת ומעבירה אותו לפונקציית הקריאה החוזרת שסופקה.
| שימוש | החזרות |
|---|
Date.evaluate(callback) | |
| ארגומנט | סוג | פרטים |
|---|
זה: computedobject | ComputedObject | המופע של ComputedObject. |
callback | פונקציה | פונקציה מהצורה function(success, failure), שמופעלת כשהשרת מחזיר תשובה. אם הבקשה הצליחה, הארגומנט success מכיל את התוצאה המוערכת. אם הבקשה נכשלה, הארגומנט failure יכיל הודעת שגיאה. |
דוגמאות
עורך הקוד (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));
});
הגדרת Python
מידע על Python API ועל שימוש ב-geemap לפיתוח אינטראקטיבי מופיע בדף
Python Environment.
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.
אלא אם צוין אחרת, התוכן של דף זה הוא ברישיון Creative Commons Attribution 4.0 ודוגמאות הקוד הן ברישיון Apache 2.0. לפרטים, ניתן לעיין במדיניות האתר Google Developers. Java הוא סימן מסחרי רשום של חברת Oracle ו/או של השותפים העצמאיים שלה.
עדכון אחרון: 2025-07-26 (שעון UTC).
[null,null,["עדכון אחרון: 2025-07-26 (שעון UTC)."],[[["\u003cp\u003e\u003ccode\u003eDate.evaluate()\u003c/code\u003e retrieves the value of a server-side \u003ccode\u003eee.Date\u003c/code\u003e object and passes it to a callback function.\u003c/p\u003e\n"],["\u003cp\u003eThe callback function receives the evaluated result as an object with \u003ccode\u003etype\u003c/code\u003e and \u003ccode\u003evalue\u003c/code\u003e keys, where \u003ccode\u003evalue\u003c/code\u003e represents milliseconds since the Unix epoch.\u003c/p\u003e\n"],["\u003cp\u003eExcessive use of \u003ccode\u003eevaluate\u003c/code\u003e can impact performance due to data transfer from Earth Engine servers to the client.\u003c/p\u003e\n"],["\u003cp\u003eThe Python client library uses \u003ccode\u003egetInfo()\u003c/code\u003e instead of \u003ccode\u003eevaluate\u003c/code\u003e for asynchronous evaluation of \u003ccode\u003eee.Date\u003c/code\u003e objects.\u003c/p\u003e\n"]]],["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,["# ee.Date.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| Date.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/**\n * WARNING: this function transfers data from Earth Engine servers to the\n * client. Doing so can negatively affect request processing and client\n * performance. Server-side options should be used whenever possible.\n * Learn more about the distinction between server and client:\n * https://developers.google.com/earth-engine/guides/client_server\n */\n\n// A server-side ee.Date object.\nvar dateServer = ee.Date('2021-4-30');\n\n// Use evaluate to transfer server-side date to the client. The result is\n// an object with keys \"type\" and \"value\" where \"value\" is milliseconds since\n// Unix epoch.\ndateServer.evaluate(function(dateClient) {\n print('Client-side date is an object', typeof dateClient);\n print('Object keys include \"type\" and \"value\"', Object.keys(dateClient));\n print('\"value\" is milliseconds since Unix epoch', dateClient.value);\n print('Client-side date in JS Date constructor', new Date(dateClient.value));\n});\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.Date objects.\n# Use ee.Date.getInfo() instead.\n```"]]
