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Dynamic Feature Extensions to the Presence Information Data Format Location Object (PIDF-LO) draft-singh-geopriv-pidf-lo-dynamic-02.txt. Vishal K. Singh Henning Schulzrinne Hannes Tschofenig IETF 70, Vancouver. Requirements and Use Cases.
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Dynamic Feature Extensions to the Presence Information Data Format Location Object (PIDF-LO)draft-singh-geopriv-pidf-lo-dynamic-02.txt Vishal K. Singh Henning Schulzrinne Hannes Tschofenig IETF 70, Vancouver
Requirements and Use Cases • Mechanism to indicate temporal features of entities = location of moving objects • Use cases: • location tracking • fewer messages than providing position samples • fleet management (trucks) • safety of personnel • Extends PIDF-LO (RFC 4119) with temporal feature elements
Dynamic Feature Elements Based on GML’s dynamicFeature.xsd • Speed • Measure of the rate of motion • Bearing • Horizontal direction of one terrestrial point from other • type gml:DirectionPropertyType • Acceleration • Change of speed • directionOfObject • Instantaneous horizontal of front of object relative to true north and vertical angle relative to earth’s spheroid • type gml:DirectionVector dropped elevation
Example <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"> <tuple id="sg89ae"> <status> <gp:geopriv> <gp:location-info> <gml:location> ………… </gml:location> <gml:speed uom="#m/s">12</temp:speed> <gml:bearing> <gml:DirectionVector> <gml:vector>270.0 -60.0</gml:vector> </gml:DirectionVector> </gml:bearing> </gp:location-info> <gp:usage-rules> ………… ………… ………… </gp:usage-rules> </gp:geopriv> </status> <timestamp>2008-06-22T20:57:29Z</timestamp> </tuple> </presence>
Indicating use of Dynamic Feature PIDF-LO using SIP • Use of SIP Accept header • Proposes use of “supported” parameter • For example: Accept: application/pidf+xml; supported="geopriv-temporal-features" • Content-Type header Content-Type: application/pidf+xml
Open Issues • Units of measurements • could also assume single default unit (m/s, m2/s) • Restrict options for bearing and directionOfObject to <vector> • others (compass point) can be translated to angles or are not interopable (DirectionKeyword) • How to indicate use of dynamic feature PIDF-LO in HELD?
Next Steps • Adopt this as WG draft • Submit a new version • Close the open issues • IANA considerations • Revise the text
Multiple Moving Object Elements • Watchers may request to receive multiple location vector objects together • Use of <timed-status> to transfer multiple location vector objects <tuple> <status> <gp:geopriv> .......... </gp:geopriv> </status> <timestamp>.....</timestamp> <timed-status from="some time" until="some time"> <gp:geopriv> ............ </gp:geopriv> <gp:geopriv> ........... </gp:geopriv> </timed-status> </tuple> <tuple> ....... </tuple>
Could use <MovingObjectStatus> or its parent element <track> from GML’s dynamicFeature.xsd But… Backward compatibility problems OR <location> appears twice tuple 1 status geopriv 1 location-info movingobjectstatus location speed location-info geopriv 2 Alternatives Considered old system won’t find <location> duplicate <location> - mandatory below <movingobjectstatus> tuple 1 status geopriv 1 location-infolocation movingobjectstatus location speed geopriv 2