View source for W3C Geolocation API

{{Infobox technology standard
| title             = Geolocation API
| long_name         =
| image             = 
| caption           = 
| status            = [[Organization:World Wide Web Consortium#W3C recommendation (REC)|W3C Recommendation]]
| year_started      = {{Start date and age|2008}}<ref name="geolocation-spec-hist">{{Cite web|url=https://www.w3.org/standards/history/geolocation-API|title=Geolocation API Specification 2nd Edition Publication History - W3C|date=n.d.|access-date=2021-04-21}}</ref><ref name="geolocation-spec-20081222">{{cite web|url=https://www.w3.org/TR/2008/WD-geolocation-API-20081222/|title=Geolocation API Specification|first=Andrei (editor, Google Inc.)|last=Popescu|website=W3C|publisher=Geolocation Working Group|date=2008-12-22|access-date=2021-04-21}}</ref>
| first_published   = {{Start date and age|2008|12|22}}<ref name="geolocation-spec-hist" /><ref name="geolocation-spec-20081222" />
| version           = W3C Recommendation
| version_date      = {{Start date and age|2016|11|08}}<ref name="geolocation-spec" />
| preview           = 
| preview_date      = 
| organization      = {{Plainlist|
* {{abbr|[[Organization:World Wide Web Consortium|W3C]]|World Wide Web Consortium}}
* [[Company:Google|Google]]
}}
| committee         = Geolocation Working Group<ref name="geolocation-spec" />
| editors           = Andrei Popescu<ref name="geolocation-spec" />
| authors           = 
| base_standards    = 
| related_standards = 
| abbreviation      = 
| domain            = Geographical location information
| license           = 
| website           = {{URL|https://www.w3.org/TR/geolocation-API/}}
}}

The '''W3C Geolocation API''' is an effort by the [[Organization:World Wide Web Consortium|World Wide Web Consortium]] (W3C) to standardize an interface to retrieve the geographical location information for a client-side device.<ref name="geolocation-spec">{{cite web |url=https://www.w3.org/TR/geolocation-API/ |title=Geolocation API Specification 2nd Edition |first=Andrei (editor, Google Inc.) |last=Popescu |website=W3C |publisher=Geolocation Working Group |date=2016-11-08 |access-date=2021-04-21 }}</ref> It defines a set of objects, [[ECMAScript]] standard compliant, that executing in the client application give the client's device location through the consulting of Location Information Servers, which are transparent for the [[Application programming interface|application programming interface]] (API). The most common sources of location information are [[IP address]], [[Wi-Fi]] and [[Bluetooth]] [[MAC address]], [[Radio-frequency identification|radio-frequency identification]] (RFID), Wi-Fi connection location, or device [[Engineering:Global Positioning System|Global Positioning System]] (GPS) and GSM/[[Engineering:CDMA2000|CDMA]] cell IDs. The location is returned with a given accuracy depending on the best location information source available.

The result of W3C Geolocation API will usually give 4 location properties, including [[Earth:Latitude|latitude]] and [[Earth:Longitude|longitude]] (coordinates), altitude (height), and accuracy [of the position gathered], which all depend on the location sources.{{Citation needed|date=February 2023}}

== Deployment in web browsers ==
Web pages can use the Geolocation API directly if the web browser implements it. Historically, some browsers could gain support via the Google Gears [[Plug-in (computing)|plugin]], but this was discontinued in 2010 and the server-side API it depended on stopped responding in 2012.<ref>{{cite web |url=https://code.google.com/apis/gears/api_geolocation.html |archive-url=https://web.archive.org/web/20120214212239/https://code.google.com/apis/gears/api_geolocation.html|title=Geolocation API: Gears API: Google Code |website=Google Code |date=9 July 2009 |archive-date=2012-02-14 |access-date=2021-04-21 }}</ref><ref name="code-google-gear-geo-api" />

The Geolocation API is ideally suited to web applications for mobile devices such as [[Social:Personal digital assistant|personal digital assistant]]s (PDA) and [[Engineering:Smartphone|smartphone]]s. On desktop computers, the W3C Geolocation API works in [[Software:Firefox|Firefox]] since version 3.5, [[Software:Google Chrome|Google Chrome]],<ref>{{cite web |url=http://chrome.blogspot.com/2010/05/new-chrome-stable-release-welcome-mac.html|title=A new Chrome stable release: Welcome, Mac and Linux!|website=Google Chrome Blog |date=25 May 2010 |access-date=2021-04-21 }}</ref> [[Software:Opera (web browser)|Opera]] 10.6,<ref>{{cite web |url=http://my.opera.com/desktopteam/blog/2010/07/01/opera-10-60-goes-final |archive-url=https://web.archive.org/web/20111109061925/http://my.opera.com/desktopteam/blog/2010/07/01/opera-10-60-goes-final|title=Opera 10.60 goes final|first=Huib|last=Kleinhout |work=My Opera |publisher=Opera Software |date=2021-07-01 |archive-date=2011-11-09 |access-date=2021-04-21 }}</ref> [[Software:Internet Explorer|Internet Explorer]] 9.0,<ref>{{cite web|title=W3C Geolocation API in IE9 - IEBlog - Site Home - MSDN Blogs|url=http://blogs.msdn.com/b/ie/archive/2011/02/17/w3c-geolocation-api-in-ie9.aspx|url-status=dead|archive-url=https://web.archive.org/web/20110219033657/http://blogs.msdn.com/b/ie/archive/2011/02/17/w3c-geolocation-api-in-ie9.aspx|author=ieblog|website=IEBlog|date=2011-02-17|archive-date=2011-02-19|access-date=2021-04-21 }}</ref> and Safari 5. On mobile devices, it works on [[Software:Android (operating system)|Android]] (firmware 2.0+), [[Software:IOS (Apple)|iOS]], [[Software:Windows Phone|Windows Phone]] and [[Software:Maemo|Maemo]]. The W3C Geolocation API is also supported by Opera Mobile 10.1 – available for Android and [[Software:Symbian|Symbian]] devices (S60 generations 3 & 5) since 24 November 2010.<ref>{{cite web|url=http://www.opera.com/press/releases/2010/11/24/ |archive-url=https://web.archive.org/web/20111104005142/http://www.opera.com/press/releases/2010/11/24/|author=Opera.com|title=Opera speeds up Symbian browsing|date=2010-11-25|archive-date=2011-11-04|access-date=2021-04-21 }}</ref> Browsers initially allowed access to the API in insecure contexts, but in the context of Secure Contexts,<ref>{{Cite web |title=Secure Contexts |url=https://www.w3.org/TR/secure-contexts/Overview.html |access-date=2022-10-13 |website=W3.org }}</ref> browsers, e.g., Chrome,<ref>{{Cite web |title=Intent to Remove: Insecure origin usage of geolocation |url=https://groups.google.com/a/chromium.org/g/blink-dev/c/ylz0Zoph76A/m/jaMAcld6BQAJ |access-date=2022-10-13 |website=Groups.Google.com }}</ref>  now generally require a secure connection.

Google Gears provided geolocation support for older and non-compliant browsers, including Internet Explorer 7.0+ as a Gears plugin, and Google Chrome which implemented Gears natively. It also supported geolocation on mobile devices as a plugin for the Android browser (pre version 2.0) and [[Software:Opera Mobile|Opera Mobile]] for [[Software:Windows Mobile|Windows Mobile]]. However, the Google Gears Geolocation API is incompatible with the W3C Geolocation API and is no longer supported.

==Location sources==

The Geolocation API does not provide the location information. The location information is obtained by a device (such as a smartphone, PC or modem), which is then served by the API to be brought in browser. Usually geolocation will try to determine a device's position using one of these several methods.

; GPS (Global Positioning System): This happens for any device which has GPS capabilities. A smartphone with GPS capabilities and set to high accuracy mode will be likely to obtain the location data from this. GPS calculate location information from the satellite signal. It has the highest accuracy; in most Android smartphones, the accuracy can be up to 10 metres.
; Mobile Network Location: [[Earth:Mobile phone tracking|Mobile phone tracking]] is used if a cellphone or wireless modem is used without a GPS chip built in.
; Wi-Fi Positioning System: If Wi-Fi is used indoors, a [[Wi-Fi positioning system]] is the likeliest source. Some Wi-Fi spots have location services capabilities.
; IP Address Location: Location is detected based on the nearest public IP address on a device (which can be a computer, the router it is connected to, or the Internet Service Provider (ISP) the router uses). The location depends on the IP information available, but in many cases where the IP is hidden behind an ISP network address translation, the accuracy is only to the level of a city, region or even country.

==Implementation==
Though the implementation is not specified, W3C Geolocation API is built on extant technologies, and is heavily influenced by Google Gears Geolocation API. Example: Firefox's Geolocation implementation<ref>{{cite web |url=https://support.mozilla.org/en-US/kb/does-firefox-share-my-location-websites?redirectslug=does-firefox-share-my-location-web-sites&redirectlocale=en-US|title=Does Firefox share my location with websites? {{!}} Mozilla Support|work=Mozilla Firefox|publisher=Mozilla|date=n.d.|access-date=2021-04-21}}</ref> uses Google's network location provider.<ref name="code-google-gear-geo-api">{{cite web |url=https://code.google.com/apis/gears/geolocation_network_protocol.html|url-status=dead|archive-url=https://web.archive.org/web/20151222162645/https://code.google.com/p/gears/wiki/GeolocationAPI|title=GeolocationAPI - gears - Provides the geolocation of a device running a Gears-enabled web browser. - Improving Your Web Browser - Google Project Hosting|work=Google Code|archive-date=2015-12-22|date=n.d.|access-date=2021-04-21}}</ref> Google Gears Geolocation works by sending a set of parameters that could give a hint as to where the user's physical location is to a network location provider server, which is by default the one provided by Google (code.l.google.com).<ref>{{cite web |url=http://webscannotes.com/?page_id=425|url-status=dead|archive-url=https://web.archive.org/web/20121112035756/http://webscannotes.com/geolocation-api/|title=WebScanNotes.com: W3C Geolocation API|work=WebScanNotes|date=n.d.|archive-date=2012-11-12|access-date=2021-04-21}}</ref> Some of the parameters are lists of sensed mobile cell towers and Wi-Fi networks, all with sensed signal strengths. These parameters are encapsulated into a JavaScript Object Notation ([[JSON]]) message and sent to the network location provider via HTTP POST. Based on these parameters, the network location provider can calculate the location.  Common uses for this location information include enforcing access controls, localizing and customizing content, analyzing traffic, contextual advertising and preventing identity theft.<ref>{{cite web|url=https://papers.ssrn.com/sol3/papers.cfm?abstract_id=1622411|ssrn=1622411 |title=Personal Jurisdiction, Internet Commerce, and Privacy: The Pervasive Legal Consequences of Modern Geolocation Technologies|first=Kevin F.|last=King|date=2010-06-08|publication-date=2010-06-09|access-date=2021-04-21}}</ref>

===Example code===
Simple [[JavaScript]] code that checks if the browser has the Geolocation API implemented and then uses it to get the current position of the device. this code creates a function which can be called on HTML using <code><body onload="geoFindMe()"></code>:
<source lang="javascript">
const geoFindMe = () => {
    if (navigator.geolocation) {
        navigator.geolocation.getCurrentPosition(success, error, geoOptions);
    } else {
        console.log("Geolocation services are not supported by your web browser.");
    }
}

const success = (position) => {
    const latitude = position.coords.latitude;
    const longitude = position.coords.longitude;
    const altitude = position.coords.altitude;
    const accuracy = position.coords.accuracy;
    console.log(`lat: ${latitude} long: ${longitude}`);
}

const error = (error) => {
    console.log(`Unable to retrieve your location due to ${error.code}: ${error.message}`);
}

const geoOptions = {
    enableHighAccuracy: true,
    maximumAge: 30000,
    timeout: 27000
};
</source>

==See also==
* [[Earth:Local search (Internet)|Local search (Internet)]]
* [[Earth:Location-based service|Location-based service]]

==References==
{{Reflist}}

==External links==
* [http://www.w3.org/TR/geolocation-API/ W3C Geolocation API Specification]

{{W3C standards}}
{{Web interfaces}}

[[Category:Application programming interfaces]]
[[Category:HTML5]]
[[Category:Location-based software]]
[[Category:Web standards]]

{{Sourceattribution|W3C Geolocation API}}