xep-0110.xml

<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE xep SYSTEM 'xep.dtd' [
  <!ENTITY % ents SYSTEM "xep.ent">
%ents;
]>
<?xml-stylesheet type='text/xsl' href='xep.xsl'?>
<xep>
<header>
  <title>Generic Maps</title>
  <abstract>A protocol for transport of generic maps (graphical displays of specific subsets of buddies).</abstract>
  &LEGALNOTICE;
  <number>0110</number>
  <status>Deferred</status>
  <type>Standards Track</type>
  <sig>Standards</sig>
  <approver>Council</approver>
  <dependencies/>
  <supersedes/>
  <supersededby/>
  <shortname>Not yet assigned</shortname>
  <author>
    <firstname>Jiri</firstname>
    <surname>Komzak</surname>
    <email>j.komzak@open.ac.uk</email>
    <jid>jkk25@jabber.open.ac.uk</jid>
  </author>
  <author>
    <firstname>Martin</firstname>
    <surname>Dzbor</surname>
    <email>m.dzbor@open.ac.uk</email>
    <jid>md267@jabber.open.ac.uk</jid>
  </author>
  <revision>
    <version>0.1</version>
    <date>2003-07-28</date>
    <initials>jk</initials>
    <remark>Initial version.</remark>
  </revision>
</header>
<section1 topic='Introduction'>
  <p>Generic maps provide a way to extending the roster into a general display showing contacts (JIDs) together with further additional information. The further information is provided by the position in the map (and possibly by the dot type - e.g. shape or colour). In addition to showing people belonging to one roster group, it is possible to cluster people, use more detailed inset maps etc. each of these features providing a unique context.</p>
  <p>The motivations for this document are:</p>
  <ul>
    <li>It is faster and easier to find people using a rich graphical view as compared to linear lists/trees</li>
    <li>Maps provide easily understandable further information (context) about the contact</li>
    <li>Maps show relations among JIDs and give better idea about their distribution in a given space (e.g. geographic region, company, campus)</li>
  </ul>
</section1>
<section1 topic='Requirements'>
  <p>The requirements for the protocol are:</p>
  <ul>
    <li>General definition of projection based on some attribute(s) of particular JIDs</li>
    <li>Scaleability - in display size and size of transmitted data</li>
  </ul>
</section1>
<section1 topic='Use Cases'>
  <p>Generic Map is actually XML description of a graphical display, which can then be sent as a part of &lt;message/&gt; or &lt;iq/&gt; packet together with information about how to obtain attributes needed for its display (other resources required).</p>
  <section2 topic='Generic Map message'>
    <p>Example 1 shows a typical message containing simple Generic Map.</p>
    <example caption='Generic map message'><![CDATA[
<message to='joe@domain.com' from='john@domain.com' id='map1'>
  <subject>Map of our office</subject>
  <body>Cool stuff, I can see you on-line in the map.</body>
  <map xmlns='http://jabber.org/protocol/map' id='map1.ygf'>
    <layer id='inset_1' offset_x='0' offset_y='0' scale='1'>
      <img src='ortho_0.gif' width='242' height='243'/>
      <item jid='buddy1@jabber.org' x='135' y='35'/>
      <item jid='buddy2@jabber.org' x='175' y='155'/>
    </layer>
  </map>
  <x xmlns=jabber:x:oob>
    <url>http://domain.com/maps/ortho_0.gif</url>
    <desc>ortho_0.gif - map for map1.ygf</desc>
  </x>
</message>
]]></example>
    <p>Each map consists of one or more layers. The main purpose of layers is to combine maps and views to deliver information suitable for a particular context, and to offer greater flexibility to the user in respect to customization.</p>
    <p>Layers can be defined either inline or by a reference to another map. Each layer has a specified position in the map, a scale and a priority. The maps defined inline contain also projection, underlying image and a list of entities lying inside it (i.e. typically JIDs or clusters of JIDs). The underlying images are sent out of band using the jabber:x:oob namespace or possibly defined in some other way (e.g. xml-based SVG).</p>
    <p>The map in Example 1 uses an implicit map projection assuming that attributes x and y are directly the co-ordinates of a particular entity (e.g. buddy1@jabber.org) in the image (ortho_0.gif) expressed in pixels.</p>
  </section2>
  <section2 topic='Definition of projection'>
    <p>A similar map with coordinates specified using geographic latitude + longitude (possibly obtained using Geographic Location Information <note>XEP-0080: Geographic Location Information <link url='http://www.xmpp.org/extensions/xep-0080.html'>http://www.xmpp.org/extensions/xep-0080.html</link></note> extension) is shown in Example 2 (only the map tag is shown).</p>
    <example caption='Generic map tag using geographic coordinates'><![CDATA[
<map xmlns='http://jabber.org/protocol/map' id='map2.ygf'>
  <layer id='inset_1' offset_x='0' offset_y='0' scale='1'>
    <img src='ortho_0.gif' width='242' height='243'/>
    <projection x='(long-5)*10' y='(lat-40)*12'/>
    <item jid='buddy1@jabber.org' long='9' lat='51'/>
    <item jid='buddy2@jabber.org' long='12' lat='52'/>
  </layer>
</map>
]]></example>
    <p>As can be seen in Example 2, the projection can be specified using any parameters either explicitly set in the item tags or obtained for the particular JID from some other source (e.g. JUD or LDAP).</p>
  </section2>
  <section2 topic='Scaleability'>
    <p>Another important feature of this proposal is scaleability, which is achieved by grouping the individual JIDs with similar properties (e.g. 'near' locations) into clusters. Cluster is basically a list of constituting entities (JIDs) that share similar values of specified attribute (e.g. JIDs that are co-located in the same town/region/country). The size of clusters may depend on the resolution and intended scale of the map. In the map clusters can be displayed using a distinctive icon.</p>
    <example caption='Generic map tag with clustered items'><![CDATA[
<map xmlns='http://jabber.org/protocol/map' id='map3.ygf'>
  <layer id='inset_1' offset_x='0' offset_y='0' scale='1'>
    <img src='ortho_0.gif' width='242' height='243'/>
    <item jid='buddy1@jabber.org' long='9' lat='51'/>
    <cluster size='10' x='38' y='135' size='5'>
      <item jid='buddy2@jabber.org'/>
      <item jid='buddy3@jabber.org'/>
    </cluster>
  </layer>
</map>
]]></example>
  </section2>
</section1>
<section1 topic='Implementation Notes'>
  <p>The following guidelines may assist the developers of a mapping plug-in in the Jabber clients.</p>
  <section2 topic='Parsing equations for map projections'>
    <p>The expression in the &lt;projection/&gt; tag uses values of different attributes specified for the JID either directly in the &lt;map/&gt; tag or elsewhere in the environment.</p>
  </section2>
  <section2 topic='Transfering image files'>
    <p>The image files (maps) are transferred as an extra extension of packet using the filename as a unique id.</p>
  </section2>
  <section2 topic='Attributes for determination of coordinates'>
    <p>The attributes are either specified in the &lt;map/&gt; tag or known in the environment (e.g. presence), but they could be also provided by a subscribed service using Publish-Subscribe <note>XEP-0060: Publish-Subscribe <link url='http://www.xmpp.org/extensions/xep-0060.html'>http://www.xmpp.org/extensions/xep-0060.html</link></note> (e.g. GPS or LBS from a mobile operator).</p>
  </section2>
  <section2 topic='Clusters - accumulation of attribute values'>
    <p>The clustering of items can be specified directly in the map tag or done using a pixel resolution of the display available.</p>
  </section2>
</section1>
<section1 topic='Security Considerations'>
  <p>No security features or concerns related to this proposal.</p>
</section1>
<section1 topic='IANA Considerations'>
  <p>No IANA interaction required.</p>
</section1>
<section1 topic='XMPP Registrar Considerations'>
  <p>The &REGISTRAR; will need to register the new namespace of "http://jabber.org/protocol/map".</p>
</section1>
</xep>