Geolocation request and response

Geolocation requests

Geolocation requests are sent using POST to the following URL:

https://www.googleapis.com/geolocation/v1/geolocate?key=YOUR_API_KEY

You must specify a key in your request, included as the value of a key parameter. A key is your application's API key. This key identifies your application for purposes of quota management. Learn how to get a key.

Request body

The request body must be formatted as JSON. If the request body is not included, the results are returned based on the IP address of request location. The following fields are supported, and all fields are optional, unless otherwise stated:

An example Geolocation API request body is shown below.

{
  "homeMobileCountryCode": 310,
  "homeMobileNetworkCode": 410,
  "radioType": "gsm",
  "carrier": "Vodafone",
  "considerIp": true,
  "cellTowers": [
    // See the Cell Tower Objects section below.
  ],
  "wifiAccessPoints": [
    // See the WiFi Access Point Objects section below.
  ]
}

Cell tower objects

The request body's cellTowers array contains zero or more cell tower objects.

The following optional fields are not used, but may be included if values are available.

Calculating cellId

Radio types prior to NR (5G) use the 32-bit cellId field for passing the network cell ID to Geolocation API.

• GSM (2G) networks use the 16-bit Cell ID (CID) as is. Valid range: 0–65535.
• CDMA (2G) networks use the 16-bit Base Station ID (BID) as is. Valid range: 0–65535.
• WCDMA (3G) networks use the UTRAN/GERAN Cell Identity (UC-ID), which is a 28-bit integer value concatenating the 12-bit Radio Network Controller Identifier (RNC-ID) and 16-bit Cell ID (CID).
  Formula: rnc_id << 16 | cid.
  Valid range: 0–268435455.
  Note: Specifying only the 16-bit Cell ID value in WCDMA networks results in incorrect or zero results.
• LTE (4G) networks use the E-UTRAN Cell Identity (ECI), which is a 28-bit integer value concatenating the 20-bit E-UTRAN Node B Identifier (eNBId) and the 8-bit Cell ID (CID).
  Formula: enb_id << 8 | cid.
  Valid range: 0–268435455.
  Note: Specifying only the 8-bit Cell ID value in LTE networks results in incorrect or zero results.

Placing values outside these ranges in the API request may result in undefined behavior. The API, at Google's discretion, may truncate the number so it fits in the documented range, infer a correction to the radioType, or return a NOT_FOUND result without any indicator in the response.

An example LTE cell tower object is below.

{
  "cellTowers": [
    {
      "cellId": 170402199,
      "locationAreaCode": 35632,
      "mobileCountryCode": 310,
      "mobileNetworkCode": 410,
      "age": 0,
      "signalStrength": -60,
      "timingAdvance": 15
    }
  ]
}

Calculating newRadioCellId

Newer networks, whose cell IDs are longer than 32 bits use the 64-bit newRadioCellId field for passing the network cell ID to Geolocation API.

• NR (5G) networks use the 36-bit New Radio Cell Identity (NCI) as is.
  Valid range: 0–68719476735.

An example NR cell tower object is below.

{
  "cellTowers": [
    {
      "newRadioCellId": 68719476735,
      "mobileCountryCode": 310,
      "mobileNetworkCode": 410,
      "age": 0,
      "signalStrength": -60,
    }
  ]
}

WiFi access point objects

The request body's wifiAccessPoints array must contain two or more WiFi access point objects representing physically distinct access point devices. macAddress is required; all other fields are optional.

An example WiFi access point object is shown below.

{
  "macAddress": "f0:d5:bf:fd:12:ae",
  "signalStrength": -43,
  "signalToNoiseRatio": 0,
  "channel": 11,
  "age": 0
}

Sample requests

If you'd like to try the Geolocation API with sample data, save the following JSON to a file:

{
  "considerIp": "false",
  "wifiAccessPoints": [
    {
      "macAddress": "3c:37:86:5d:75:d4",
      "signalStrength": -35,
      "signalToNoiseRatio": 0
    },
    {
      "macAddress": "30:86:2d:c4:29:d0",
      "signalStrength": -35,
      "signalToNoiseRatio": 0
    }
  ]
}

You can then use cURL to make your request from the command line:

$ curl -d @your_filename.json -H "Content-Type: application/json" -i "https://www.googleapis.com/geolocation/v1/geolocate?key=YOUR_API_KEY"

The response for the preceding MAC addresses looks like this:

{
  "location": {
    "lat": 37.4241173,
    "lng": -122.0915717
  },
  "accuracy": 20
}

Dropping unused WiFi access points

Removing WiFi access point objects with macAddresses that are locally-administered can improve the success rate of Geolocation API calls that use WiFi as input. If, after filtering, it can be determined that a Geolocation API call would not succeed, mitigations such as using older location signals or WiFi APs with weaker signals can be used. This approach is a tradeoff between your application's need for a location estimate and its precision and recall requirements. The following filtering techniques demonstrate how to filter the inputs, but do not show the mitigations that you may, as the application engineer, choose to apply.

Locally administered MAC addresses are not useful location signals for the API and are silently dropped from requests. You can remove such MAC addresses by ensuring that the second least-significant bit of the macAddress's most-significant byte is 0, e.g. the 1 bit represented by the 2 in 02:00:00:00:00:00. The broadcast MAC address (FF:FF:FF:FF:FF:FF) is an example of a MAC address that would be usefully excluded by this filter.

The range of MAC addresses between 00:00:5E:00:00:00 and 00:00:5E:FF:FF:FF are reserved for IANA and often used for network management and multicast functions which precludes their use as a location signal. You should also remove these MAC addresses from inputs to the API.

For example, usable MAC addresses for Geolocation can be gathered from an array of macAddress strings named macs:

String[] macs = {"12:34:56:78:9a:bc", "1c:34:56:78:9a:bc", "00:00:5e:00:00:01"};
ArrayList<String> _macs = new ArrayList<>(Arrays.asList(macs));
_macs.removeIf(m -> !(0 == (2 & Integer.parseInt(m.substring(1, 2), 16))
                      && !m.substring(0, 8).toUpperCase().equals("00:00:5E")));
    

macs = ['12:34:56:78:9a:bc', '1c:34:56:78:9a:bc', '00:00:5e:00:00:01']
macs = [m for m in macs if (0 == (2 & int(m[1], 16)) and m[:8].upper() != '00:00:5E')]
    

macs = ['12:34:56:78:9a:bc', '1c:34:56:78:9a:bc', '00:00:5e:00:00:01'];
macs = macs.filter(m => 0 === (2 & Number.parseInt(m[1], 16))
                           && m.substr(0, 8).toUpperCase() !== '00:00:5E');
    

Using this filter results in only 1c:34:56:78:9a:bc remaining in the list. Because this list has fewer than 2 WiFi MAC addresses, the request would not be successful and an HTTP 404 (notFound) response would be returned.

Geolocation responses

A successful geolocation request returns a JSON-formatted response defining a location and radius.

• location: The user's estimated latitude and longitude coordinates, in degrees. Contains one lat and one lng subfield.
• accuracy: The accuracy of the estimated location, in meters. This represents the radius of a circle around the given location.

{
  "location": {
    "lat": 37.421875199999995,
    "lng": -122.0851173
  },
  "accuracy": 120
}