<abstract>This document defines an XMPP protocol extension for communicating information about the current geographical location of an entity.</abstract>
<remark><p>Changed xs:string to xs:decimal for bearing and specified that bearing is to be interpreted as decimal degrees relative to true north.</p></remark>
</revision>
<revision>
<version>1.1</version>
<date>2004-10-29</date>
<initials>psa</initials>
<remark><p>Changed xs:int to xs:decimal for altitude; changed MUST NOT to SHOULD NOT regarding inferences about accuracy.</p></remark>
</revision>
<revision>
<version>1.0</version>
<date>2004-10-12</date>
<initials>psa</initials>
<remark><p>Per a vote of the Jabber Council, advanced status to Draft; also added internationalization considerations and linked to an archived version of the GPS datum example.</p></remark>
</revision>
<revision>
<version>0.9</version>
<date>2004-10-12</date>
<initials>psa</initials>
<remark><p>Clarified several points in the implementation notes.</p></remark>
</revision>
<revision>
<version>0.8</version>
<date>2004-09-15</date>
<initials>psa</initials>
<remark><p>Specified error flow for IQ example.</p></remark>
<p>This document defines a format for capturing data about an entity's geographical location (geoloc). The format defined herein can describe most earthbound geographical locations, especially locations that may change fairly frequently. Potential uses for this approach include:</p>
<ul>
<li>Publishing location information to a set of subscribers.</li>
<li>Querying another entity for its location.</li>
<li>Sending location information to another entity.</li>
<li>Attaching location information to presence.</li>
</ul>
<p>Geographical location is captured in terms of Global Positioning System (GPS) coordinates as well as civil location (city, street, building, etc.).</p>
</section1>
<section1topic='Requirements'anchor='reqs'>
<p>The format defined herein was designed to address the following requirements:</p>
<ul>
<li>It shall be possible to encapsulate location in terms of Global Positioning System (GPS) coordinates as well as civil location (city, street, building, etc.).</li>
<li>The GPS encoding mechanism shall have a single set of units, so that receivers do not need to use heuristics to determine an entity's position.</li>
<li>It shall be possible to specify the known amount of error in the GPS coordinates.</li>
<li>It shall be possible to include a natural-language description of the location.</li>
</ul>
</section1>
<section1topic='Data Format'anchor='format'>
<p>Information about the entity's location is provided by the entity and propagated on the network by the entity's associated application (usually a client). The information is structured by means of a <geoloc/> element that is qualified by the 'http://jabber.org/protocol/geoloc' namespace; the geolocation information itself is provided as the XML character data of the following child elements:</p>
<tablecaption='Child Elements'>
<tr>
<th>Element Name</th>
<th>Datatype</th>
<th>Definition</th>
<th>Example</th>
</tr>
<tr>
<td>alt</td>
<td>xs:decimal</td>
<td>Altitude in meters above or below sea level</td>
<td>1609</td>
</tr>
<tr>
<td>area</td>
<td>xs:string</td>
<td>A named area such as a campus or neighborhood</td>
<td>Central Park</td>
</tr>
<tr>
<td>bearing</td>
<td>xs:decimal</td>
<td>GPS bearing (direction in which the entity is heading to reach its next waypoint), measured in decimal degrees relative to true north <note>It is the responsibility of the receiver to translate bearing into decimal degrees relative to magnetic north, if desired.</note></td>
<td> </td>
</tr>
<tr>
<td>building</td>
<td>xs:string</td>
<td>A specific building on a street or in an area</td>
<td>The Empire State Building</td>
</tr>
<tr>
<td>country</td>
<td>xs:string</td>
<td>The nation where the user is located</td>
<td>USA</td>
</tr>
<tr>
<td>datum</td>
<td>xs:string</td>
<td>GPS datum <note>If datum is not included, receiver MUST assume WGS84; receivers MUST implement WGS84; senders MAY use another datum, but it is not recommended.</note></td>
<td> </td>
</tr>
<tr>
<td>description</td>
<td>xs:string</td>
<td>A natural-language name for or description of the location</td>
<td>Bill's house</td>
</tr>
<tr>
<td>error</td>
<td>xs:decimal</td>
<td>Horizontal GPS error in arc minutes</td>
<td>10</td>
</tr>
<tr>
<td>floor</td>
<td>xs:string</td>
<td>A particular floor in a building</td>
<td>102</td>
</tr>
<tr>
<td>lat</td>
<td>xs:decimal</td>
<td>Latitude in decimal degrees North</td>
<td>39.75</td>
</tr>
<tr>
<td>locality</td>
<td>xs:string</td>
<td>A locality within the administrative region, such as a town or city</td>
<td>New York City</td>
</tr>
<tr>
<td>lon</td>
<td>xs:decimal</td>
<td>Longitude in decimal degrees East</td>
<td>-104.99</td>
</tr>
<tr>
<td>postalcode</td>
<td>xs:string</td>
<td>A code used for postal delivery</td>
<td>10027</td>
</tr>
<tr>
<td>region</td>
<td>xs:string</td>
<td>An administrative region of the nation, such as a state or province</td>
<td>New York</td>
</tr>
<tr>
<td>room</td>
<td>xs:string</td>
<td>A particular room in a building</td>
<td>Observatory</td>
</tr>
<tr>
<td>street</td>
<td>xs:string</td>
<td>A thoroughfare within the locality, or a crossing of two thoroughfares</td>
<td>34th and Broadway</td>
</tr>
<tr>
<td>text</td>
<td>xs:string</td>
<td>A catch-all element that captures any other information about the location</td>
<p>The location information SHOULD be communicated by means of &xep0060; or the subset of pubsub defined in &xep0163;. Because location information is not pure presence information and can change independently of the user's availability, it SHOULD NOT be provided as an extension to &PRESENCE;, although an application MAY do so if necessary.</p>
<p>In order to provide information about one's location, the publishing entity should use the pubsub protocol (the following examples show use of the publish-subscribe subset specified in <cite>XEP-0163</cite>).</p>
<section2topic='Entity requests the location of another entity'anchor='usecases-request'>
<p>If an entity wishes to request the location of another entity but the requestee does not publish that information via pubsub (including PEP), the requestor MAY send an IQ to the requestee:</p>
<p>If the receiving entity decides not to return the actual location, it MUST return an IQ error, which SHOULD be &forbidden; but MAY be some other appropriate error, such as ¬allowed;:</p>
<examplecaption='Access to location information denied'><