Network Working Group                                           V. Singh
Internet-Draft
Intended status:  Experimental                            H. Schulzrinne
Expires:  May 3, 2009                                Columbia University
                                                           H. Tschofenig
                                                  Nokia Siemens Networks
                                                        October 30, 2008


   Dynamic Feature Extensions to the Presence Information Data Format
                       Location Object (PIDF-LO)
               draft-singh-geopriv-pidf-lo-dynamic-04.txt

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Abstract

   The Geopriv Location Object introduced by the Presence Information
   Data Format - Location Object (PIDF-LO), RFC 4119, defines a basic
   XML format for carrying geographical information of a presentity.
   The PIDF-LO specification made a subset of the functionality offered
   by the Geography Markup Language (GML) standard 3.0 mandatory to
   implement.  This document defines child elements to the <location-
   info> element specified in RFC 4119 to carry temporal feature
   elements useful for tracking moving objects.  It defines five



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   elements, namely speed, bearing, acceleration elevation and
   directionOfObject.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  3
   3.  XML Extensions . . . . . . . . . . . . . . . . . . . . . . . .  3
   4.  XML Schema . . . . . . . . . . . . . . . . . . . . . . . . . .  4
   5.  Example  . . . . . . . . . . . . . . . . . . . . . . . . . . .  4
   6.  Security Considerations  . . . . . . . . . . . . . . . . . . .  5
   7.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . .  5
   8.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . .  6
   9.  References . . . . . . . . . . . . . . . . . . . . . . . . . .  6
     9.1.  Normative References . . . . . . . . . . . . . . . . . . .  6
     9.2.  Informative References . . . . . . . . . . . . . . . . . .  6
   Appendix A.  Transferring Multiple Location Objects within SIP . .  6
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . .  9
   Intellectual Property and Copyright Statements . . . . . . . . . . 10































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1.  Introduction

   The Presence Information Data Format - Location Object (PIDF-LO) (see
   RFC 4119 [RFC4119]) provides geographical location of the presentity.
   This corresponds to a physical location at a given instance of time.
   The PIDF-LO specification made a subset of the functionality offered
   by the Geography Markup Language (GML) standard 3.0 mandatory to
   implement.  With the extensions defined in
   [I-D.ietf-geopriv-pdif-lo-profile] more guidelines to implementers
   are being provided with respect to a number of location shapes that
   have to be supported for usage within PIDF-LO.  However, a number of
   applications benefit from having access to information about changes
   in location.  Location change information is likely to be useful for
   logistics and public safety.  For example, shipping companies or
   dispatch centers can use it to track whether vehicles are deviating
   from an established path or exceeding speed limits.


2.  Terminology

   In this document, the key words "MUST", "MUST NOT", "REQUIRED",
   "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY",
   and "OPTIONAL" are to be interpreted as described in RFC 2119
   [RFC2119].


3.  XML Extensions

   This document defines a location vector by adding child elements to
   the <location-info> element described in RFC 4119 [RFC4119], to carry
   temporal feature elements.  A receiver MAY ignore the temporal
   elements defined in this document if it does not understand this
   extension.

   speed:

      Speed is the rate of motion.  (The terms speed and velocity are
      often used interchangeably, but speed is a scalar, having
      magnitude only, while velocity is a vector, having both magnitude
      and direction.)

      This element contains a 'uom' (Units Of Measure) attribute, which
      is a reference to a reference system for the amount.  The 'uom'
      attribute uses a URI to refer to a unit of measure definition.
      The GML document defines a set of convenience measure types and a
      further explaination is provided at the end of this section.





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   bearing:

      Bearing is defined as the horizontal direction of one terrestrial
      point from another, expressed as the angular distance from a
      reference direction.  It is usually measured from 000 degrees at
      the reference direction clockwise through 360 degrees.

      The <bearing> element is of type gml:DirectionPropertyType and
      contains a gml:DirectionVector, gml:CompassPoint,
      DirectionKeyword, or a DirectionString element.  This document
      profiles the usage of this GML element and mandates applications
      using this document to make use of the <DirectionVector> element
      only.

   acceleration:

      This element specifies the rate (usually rapid) at which something
      happens.  The <acceleration> element also contains a 'uom'
      attribute.

   directionOfObject:

      The <directionOfObject> describes the instantaneous horizontal of
      the front of the object relative to true north and the vertical
      angle relative to the earth's spheroid.  It uses the GML
      <directionVector> element.

   GML permits a range of units of measure for the uom attribute.  This
   document restricts this set to the #m/s (meters per second).


4.  XML Schema

   This document does not define a new schema but instead re-uses a
   subset of the dynamicFeature.xsd schema available with GML 3.1.1,
   namely <speed>, <bearing>, <acceleration>, and <directionOfObject>.

   These four elements are conveyed inside the <location-info> element
   defined by RFC 4119 [RFC4119].


5.  Example

   The following example shows a PIDF-LO document indicating geospatial
   location information using the gml:Point structure.  Following the
   <gml:location> element the additional fields releated to temporal
   characteristics are included.




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   <?xml version="1.0" encoding="UTF-8"?>
   <presence xmlns="urn:ietf:params:xml:ns:pidf"
     xmlns:gp="urn:ietf:params:xml:ns:pidf:geopriv10"
     xmlns:gml="http://www.opengis.net/gml"
     entity="pres:geotarget@example.com">

     <device id="sg89ae">
         <gp:geopriv>
           <gp:location-info>
             <gml:location>
               <gml:Point srsName="urn:ogc:def:crs:EPSG::4326">
                 <gml:pos>-34.407 150.883</gml:pos>
               </gml:Point>
             </gml:location>
             <gml:speed uom="#m/s">12</gml:speed>
             <gml:bearing>
               <gml:DirectionVector>
                 <gml:vector> 270.0 -60.0</gml:vector>
               </gml:DirectionVector>
             </gml:bearing>
           </gp:location-info>
           <gp:usage-rules>
             <gp:retransmission-allowed>no</gp:retransmission-allowed>
             <gp:retention-expiry>2003-06-23T04:57:29Z
             </gp:retention-expiry>
           </gp:usage-rules>
         </gp:geopriv>
       <timestamp>2008-06-22T20:57:29Z</timestamp>
     </device>

   </presence>

           Figure 1: Example of a PIDF-LO with Speed Information


6.  Security Considerations

   This document defines additional location elements carried by PIDF-LO
   (see [RFC4119]).  The security considerations of RFC 4119 [RFC4119]
   are applicable to this document.


7.  IANA Considerations

   This document does not require actions by IANA.






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8.  Acknowledgements

   We would like to thank Klaus Darilion, Cullen Jennings, Rohan Mahy,
   Carl Reed, Brian Rosen, and Martin Thomson for their comments.


9.  References

9.1.  Normative References

   [GML]      "Geographic information - Geography Markup Language (GML),
              OpenGIS 03-105r1, available at:
              http://portal.opengeospatial.org/files/?artifact_id=4700",
              April 2004.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", RFC 2119, BCP 14, March 1997.

   [RFC4119]  Peterson, J., "A Presence-based GEOPRIV Location Object
              Format", RFC 4119, December 2005.

   [RFC4481]  Schulzrinne, H., "Timed Presence Extensions to the
              Presence Information Data Format (PIDF) to Indicate Status
              Information for Past and Future Time Intervals", RFC 4481,
              July 2006.

9.2.  Informative References

   [I-D.ietf-geopriv-pdif-lo-profile]
              Winterbottom, J., Thomson, M., and H. Tschofenig, "GEOPRIV
              PIDF-LO Usage Clarification, Considerations and
              Recommendations", draft-ietf-geopriv-pdif-lo-profile-13
              (work in progress), September 2008.


Appendix A.  Transferring Multiple Location Objects within SIP

   To show the path of an object, it may be useful to deliver multiple
   location vector objects in one PIDF-LO document to reduce the number
   of notifications.  The <timed-presence> element [RFC4481] can contain
   multiple location objects, with the structure shown in Figure 2 and
   an example in Figure 3.









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      <?xml version="1.0" encoding="UTF-8"?>
      <presence>

            <device>

                  <gp:geopriv>
                   ..........
                  </gp:geopriv>

                  <timestamp>.....</timestamp>

                  <timed-status from="start-time" until="end-time">
                       <gp:geopriv>
                       ............
                       </gp:geopriv>

                       <gp:geopriv>
                       ...........
                       </gp:geopriv>

                  </timed-status>
            </device>

            <tuple>
            .......
            </tuple>

            <person>
            .......
            </person>
      </presence>


         Figure 2: Structure of Handling Multiple Location Objects

   The following example shows multiple PIDF-LO using <timed-status>.


<?xml version="1.0" encoding="UTF-8"?>
<presence xmlns="urn:ietf:params:xml:ns:pidf"
  xmlns:gp="urn:ietf:params:xml:ns:pidf:geopriv10"
  xmlns:gml="urn:opengis:specification:gml:schema-xsd:feature:v3.0"
  entity="pres:geotarget@example.com">
  <device id="sg89ae">
         <gp:geopriv>
           <gp:location-info>
               <gml:location>
                  <gml:Point>



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                     <gml:pos>140. -35.</gml:pos>
                  </gml:Point>
               </gml:location>
           <gml:speed uom="#m/s">12</gml:speed>
           </gp:location-info>
           <gp:usage-rules>
             <gp:retransmission-allowed>no</gp:retransmission-allowed>
             <gp:retention-expiry>2003-06-23T04:57:29Z
             </gp:retention-expiry>
           </gp:usage-rules>
         </gp:geopriv>
       <timestamp>2003-06-22T20:57:29Z</timestamp>

       <timed-statusfrom="2005-08-15T10:20:00.000-05:00"
          until="2005-08-22T19:30:00.000-05:00">>
          <gp:geopriv>
            <gp:location-info>
               <gml:location>
                  <gml:Point>
                     <gml:pos>110. -35.</gml:pos>
                  </gml:Point>
               </gml:location>
               <gml:speed uom="#m/s">10</gml:speed>
           </gp:location-info>
            <gp:usage-rules>
              <gp:retransmission-allowed>yes</gp:retransmission-allowed>
              <gp:retention-expiry>2003-06-23T04:55:29Z
              </gp:retention-expiry>
            </gp:usage-rules>
          </gp:geopriv>
          <gp:geopriv>
            <gp:location-info>
               <gml:location>
                  <gml:Point>
                     <gml:pos>114. -35.</gml:pos>
                  </gml:Point>
               </gml:location>
               <gml:speed uom="#m/s">18</gml:speed>
            </gp:location-info>
           <gp:usage-rules>
             <gp:retransmission-allowed>yes</gp:retransmission-allowed>
             <gp:retention-expiry>2003-06-23T04:53:29Z
             </gp:retention-expiry>
           </gp:usage-rules>
         </gp:geopriv>
       </timed-status>

     </device>



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</presence>

      Figure 3: Example showing multiple Location Vectors transmitted
                              simultaneously.


Authors' Addresses

   Singh Vishal


   Email:  singh.vishal@gmail.com


   Henning Schulzrinne
   Columbia University
   Department of Computer Science
   450 Computer Science Building, New York, NY  10027
   US

   Phone:  +1 212 939 7004
   Email:  hgs@cs.columbia.edu
   URI:    http://www.cs.columbia.edu


   Hannes Tschofenig
   Nokia Siemens Networks
   Linnoitustie 6
   Espoo  02600
   Finland

   Phone:  +358 (50) 4871445
   Email:  Hannes.Tschofenig@gmx.net
   URI:    http://www.tschofenig.priv.at

















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