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Versions: (draft-thomson-geopriv-relative-location) 00 01 02 03 04 05 06 07 08 RFC 7035

GEOPRIV                                                       M. Thomson
Internet-Draft                                                 Microsoft
Intended status: Standards Track                                B. Rosen
Expires: September 20, 2013                                      Neustar
                                                              D. Stanley
                                                          Aruba Networks
                                                                G. Bajko
                                                                   Nokia
                                                              A. Thomson
                                                     Cisco Systems, Inc.
                                                          March 19, 2013


                    Relative Location Representation
              draft-ietf-geopriv-relative-location-04.txt

Abstract

   This document defines an extension to PIDF-LO (RFC4119) for the
   expression of location information that is defined relative to a
   reference point.  The reference point may be expressed as a geodetic
   or civic location, and the relative offset may be one of several
   shapes.  Optionally, a reference to a secondary document (such as a
   map image) can be included, along with the relationship of the map
   coordinate system to the reference/offset coordinate system to allow
   display of the map with the reference point and the relative offset.
   Also included in this document is a Type/Length/Value (TLV)
   representation of the relative location for use in other protocols
   that use TLVs.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on September 20, 2013.





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Copyright Notice

   Copyright (c) 2013 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Conventions used in this document . . . . . . . . . . . . . .   3
   3.  Overview  . . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Relative Location . . . . . . . . . . . . . . . . . . . . . .   6
     4.1.  Relative Coordinate System  . . . . . . . . . . . . . . .   6
     4.2.  Placement of XML Elements . . . . . . . . . . . . . . . .   7
     4.3.  Binary Format . . . . . . . . . . . . . . . . . . . . . .   7
     4.4.  Distances and Angles  . . . . . . . . . . . . . . . . . .   8
     4.5.  Value Encoding  . . . . . . . . . . . . . . . . . . . . .   8
     4.6.  Relative Location Restrictions  . . . . . . . . . . . . .   8
     4.7.  Baseline TLVs . . . . . . . . . . . . . . . . . . . . . .   8
     4.8.  Reference TLV . . . . . . . . . . . . . . . . . . . . . .   8
     4.9.  Shapes  . . . . . . . . . . . . . . . . . . . . . . . . .   9
       4.9.1.  Point . . . . . . . . . . . . . . . . . . . . . . . .   9
       4.9.2.  Circle or Sphere Shape  . . . . . . . . . . . . . . .  10
       4.9.3.  Ellipse or Ellipsoid Shape  . . . . . . . . . . . . .  11
       4.9.4.  Polygon or Prism Shape  . . . . . . . . . . . . . . .  13
       4.9.5.  Arc-Band Shape  . . . . . . . . . . . . . . . . . . .  15
     4.10. Dynamic Location TLVs . . . . . . . . . . . . . . . . . .  17
       4.10.1.  Orientation  . . . . . . . . . . . . . . . . . . . .  17
       4.10.2.  Speed  . . . . . . . . . . . . . . . . . . . . . . .  17
       4.10.3.  Heading  . . . . . . . . . . . . . . . . . . . . . .  17
     4.11. Secondary Map Metadata  . . . . . . . . . . . . . . . . .  17
       4.11.1.  Map URL  . . . . . . . . . . . . . . . . . . . . . .  18
       4.11.2.  Map Coordinate Reference System  . . . . . . . . . .  18
       4.11.3.  Map Example  . . . . . . . . . . . . . . . . . . . .  20
   5.  Examples  . . . . . . . . . . . . . . . . . . . . . . . . . .  21
     5.1.  Civic PIDF with Polygon Offset  . . . . . . . . . . . . .  21
     5.2.  Geo PIDF with Circle Offset . . . . . . . . . . . . . . .  22
     5.3.  Civic TLV with Point Offset . . . . . . . . . . . . . . .  23
   6.  Schema Definition . . . . . . . . . . . . . . . . . . . . . .  24



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   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  26
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  27
     8.1.  Relative Location Registry  . . . . . . . . . . . . . . .  27
     8.2.  URN Sub-Namespace Registration  . . . . . . . . . . . . .  28
     8.3.  XML Schema Registration . . . . . . . . . . . . . . . . .  29
     8.4.  CRS public identifier registration  . . . . . . . . . . .  30
     8.5.  CAtype Registration . . . . . . . . . . . . . . . . . . .  31
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  31
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  31
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  31
     10.2.  Informative References . . . . . . . . . . . . . . . . .  33
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  33

1.  Introduction

   This document describes a format for the expression of relative
   location information.

   A relative location is formed of a reference location, plus a
   relative offset from that reference location.  The reference location
   can be represented in either civic or geodetic form.  The reference
   location can also have dynamic components such as velocity.  The
   relative offset is specified in meters using a Cartesian coordinate
   system.

   In addition to the relative location, an optional URI can be provided
   to a document that contains a map, floorplan or illustration.
   Applications could use this information to display the relative
   location.  Additional fields allow the map to be oriented and scaled
   correctly.

   Two formats are included: an XML form that is intended for use in
   PIDF-LO [RFC4119] and a TLV format for use in other protocols such as
   those that already convey binary representation of location
   information defined in [RFC4776].

2.  Conventions used in this document

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

3.  Overview

   This document describes an extension to PIDF-LO [RFC4119] as updated
   by [RFC5139] and [RFC5491], to allow the expression of a location as
   an offset relative to a reference.




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   This extension effectively allows the creator of a location object to
   include two location values plus an offset.  The "baseline" location
   that is given outside of the <relative-location> element is what will
   be visible to a client that does not understand that extension (i.e.,
   one that ignores the <relative-location> element).  A client that
   does understand this extension will interpret the location within the
   relative element as a refinement of the baseline location, which
   gives the reference location for the relative offset.

   Creators of location objects with relative location thus have a
   choice of how much information to put into the "baseline" location
   and how much to put into the "reference" location.  For example, all
   location information could be put inside the <relative-location>
   element, so that clients that do not understand relative location
   would receive no location information at all.  Alternatively, the
   baseline location value could be precise enough to specify a building
   that contains the relative location, and the reference location could
   specify a point within the building from which the offset is
   measured.

   The baseline location SHOULD be general enough to describe both the
   reference location and the relative location (reference plus offset).
   In particular, while it is possible to put all location information
   into the "reference" location (leaving an universally broad
   "baseline"), location objects SHOULD NOT have all location
   information in the baseline location.  Doing this would cause clients
   that do not understand relative location to incorrectly interpret the
   baseline location (i.e., the reference point) as the actual, precise
   location of the client.

   Both the baseline and the reference location are defined either as a
   geodetic location [OGC.GeoShape] or a civic address [RFC4776].  If
   the baseline location was expressed as a geodetic location, the
   reference MUST be geodetic.  If the baseline location was expressed
   as a civic address, the reference MUST be a civic.

   Baseline and reference locations MAY also include dynamic location
   information [RFC5962].

   The relative location can be expressed using a point (2- or
   3-dimensional), or a shape that includes uncertainty: circle, sphere,
   ellipse, ellipsoid, polygon, prism or arc-band.  Descriptions of
   these shapes can be found in [RFC5491].

   Optionally, a reference to a 'map' document can be provided.  The
   reference is a URI.  The document could be an image or dataset that
   represents a map, floorplan or other form.  The type of document the
   URI points to is described as a MIME media type.  Metadata in the



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   relative location can include the location of the reference point in
   the map as well as an orientation (angle from North) and scale to
   align the document Co-ordinate Reference System (CRS) with the WGS84
   [WGS84] CRS.  The document is assumed to be useable by the
   application receiving the PIDF with the relative location to locate
   the reference point in the map.  This document does not describe any
   mechanisms for displaying or manipulating the document other than
   providing the reference location, orientation and scale.

   As an example, consider a relative location expressed as a point,
   relative to a civic location:

   <presence xmlns="urn:ietf:params:xml:ns:pidf"
             xmlns:dm="urn:ietf:params:xml:ns:pidf:data-model"
             xmlns:gp="urn:ietf:params:xml:ns:pidf:geopriv10"
             xmlns:ca="urn:ietf:params:xml:ns:pidf:geopriv10:civicAddr"
             xmlns:rel="urn:ietf:params:xml:ns:pidf:geopriv10:relative"
             xmlns:gml="http://www.opengis.net/gml"
             xmlns:gs="http://www.opengis.net/pidflo/1.0"
             entity="pres:relative@example.com">
     <dm:device id="relative1">
       <gp:geopriv>
         <gp:location-info>
           <ca:civicAddress xml:lang="en-AU">
             <ca:country>AU</ca:country>
             <ca:A1>NSW</ca:A1>
             <ca:A3>Wollongong</ca:A3>
             <ca:A4>North Wollongong</ca:A4>
             <ca:RD>Flinders</ca:RD>
             <ca:STS>Street</ca:STS>
             <ca:HNO>123</ca:HNO>
           </ca:civicAddress>
           <rel:relative-location>
             <rel:reference>
               <ca:civicAddress xml:lang="en-AU">
                 <ca:INT N="Door" R="A">Front</ca:INT>
               </ca:civicAddress>
             </rel:reference>
             <rel:offset>
               <gml:Point xmlns:gml="http://www.opengis.net/gml"
                          srsName="urn:ietf:params:geopriv:relative:2d">
                 <gml:pos>100 50</gml:pos>
               </gml:Point>
             </rel:offset>
           </rel:relative-location>
         </gp:location-info>
         <gp:usage-rules/>
         <gp:method>GPS</gp:method>



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         <rel:map>
           <rel:url type="image/png">
              http://example.com/location/map.png
           </rel:url>
           <rel:offset>20. 120.</rel:offset>
           <rel:orientation>29.</rel:orientation>
           <rel:scale>20. -20.</rel:scale>
         </rel:map>
       </gp:geopriv>
       <dm:deviceID>mac:1234567890ab</dm:deviceID>
       <dm:timestamp>2007-06-22T20:57:29Z</dm:timestamp>
     </dm:device>
   </presence>


4.  Relative Location

   Relative location is a shape (point, circle, ellipse...).  The shape
   is defined with a CRS that has a datum defined as the reference
   (which appears as a civic address or geodetic location in the tuple),
   and the shape coordinates as meter offsets North/East of the datum
   measured in meters (with an optional Z offset relative to datum
   altitude).  An optional angle allows the reference CRS be to rotated
   with respect to North.

4.1.  Relative Coordinate System

   The relative coordinate reference system uses a coordinate system
   with two or three axes.

   The baseline and reference locations are used to define a relative
   datum.  The reference location defines the origin of the coordinate
   system.  The centroid of the reference location is used when the
   reference location contains any uncertainty.

   The axes in this coordinate system are originally oriented based on
   the directions of East, North and Up from the reference location: the
   first (x) axis increases to the East, the second (y) axis points
   North, and the optional third (z) axis points Up.  All axes of the
   coordinate system use meters as a basic unit.

   Any coordinates in the relative shapes use the described Cartesian
   coordinate system.  In the XML form, this uses a URN of
   "urn:ietf:params:geopriv:relative:2d" for two-dimensional shapes and
   "urn:ietf:params:geopriv:relative:3d" for three-dimensional shapes.
   The binary form uses different shape type identifiers for 2D and 3D
   shapes.




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   Dynamic location information [RFC5962] in the baseline or reference
   location alters relative coordinate system.  The resulting Cartesian
   coordinate system axes are rotated so that the 'y' axis is oriented
   along the direction described by the <orientation> element.  The
   coordinate system also moves as described by the <speed> and
   <heading> elements.

4.2.  Placement of XML Elements

   The baseline of the reference location is represented as <location-
   info> like a normal PIDF-LO.  Relative location adds a new <relative-
   location> element to <location-info>.  Within <relative-location>,
   <reference> and <offset> elements are described.  Within <offset> are
   the shape elements described below.  This document extends PIDF-LO as
   described in [RFC6848].

4.3.  Binary Format

   This document describes a way to encode the relative location in a
   binary TLV form for use in other protocols that use TLVs to represent
   location.

   A type-length-value encoding is used.

   +------+------+------+------+------+------+------+
   | Type |Length|  Value                         ...
   +------+------+------+------+------+------+
   |  X   |  N   |  Value                         ...
   +------+------+------+------+------+------+------+

                        Figure 1: TLV-tuple format

   Type field (X) is defined as a single byte.  The type codes used are
   registered an IANA-managed 'RLtypes' registry defined by this
   document, and restricted to not include the values defined by the
   CAtypes registry.  This restriction permits a location reference and
   offset to be coded with unique TLVs.

   The Length field (N) is defined as an unsigned integer that is one
   byte in length.  This field can encode values from 0 to 255.  The
   length field describes the number of bytes in the Value.  Length does
   not count the bytes used for the Type or Length.

   The Value field is defined separately for each type.

   Each element of the relative location has a unique TLV assignment.  A
   relative location encoded in TLV would have the baseline location
   TLVs and a reference location TLV which contains within it the



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   reference refinement TLVs.  The reference TLVs are followed by the
   relative offset, and optional map TLDs described in this document.

4.4.  Distances and Angles

   All distance measures used in shapes are expressed in meters.

   All orientation angles used in shapes are expressed in degrees.
   Orientation angles are measured from WGS84 Northing to Easting with
   zero at Northing.  Orientation angles in the relative coordinate
   system start from the second coordinate axis (y or Northing) and
   increase toward the first axis (x or Easting).

4.5.  Value Encoding

   The binary form uses single-precision floating point values IEEE 754
   [IEEE.754] to represent coordinates, distance and angle measures.
   Single precision values are 32-bit values with a sign bit, 8 exponent
   bits and 23 fractional bits.

   Binary-encoded coordinate values are considered to be a single value
   without uncertainty.  When encoding a value that cannot be exactly
   represented, the best approximation MUST be selected according to
   [Clinger1990].

4.6.  Relative Location Restrictions

   More than one relative shape MUST NOT be included in either a PIDF-LO
   or TLV encoding of location for a given reference point.

   Any error in the reference point transfers to the location described
   by the relative location.  Any errors arising from an implementation
   not supporting or understanding elements of the reference point
   directly increases the error (or uncertainty) in the resulting
   location.

4.7.  Baseline TLVs

   Baseline locations are described using the formats defined in
   [RFC4776] or [RFC6225].

4.8.  Reference TLV

   When a reference is encoded in binary form, the baseline and
   reference locations are combined in a reference TLV.  This TLV
   contains civic address TLVs (if the baseline was a civic) or geo TLVs
   (if the baseline was a geo).




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   +------+------+------+------+------+------+
   |  111 |Length|  Reference TLVs           |
   +------+------+------+------+------+------+

                               Reference TLV

4.9.  Shapes

   Shape data is used to represent regions of uncertainty for the
   reference and relative locations.  Shape data in the reference
   location uses a [WGS84] CRS.  Shape data in the relative location
   uses a relative CRS.

   The XML form for shapes uses Geography Markup Language (GML)
   [OGC.GML-3.1.1], consistent with the rules in [RFC5491].  Reference
   locations use the CRS URNs specified in [RFC5491]; relative locations
   use either a 2D CRS (urn:ietf:params:geopriv:relative:2d), or a 3D
   (urn:ietf:params:geopriv:relative:3d), depending on the shape type.

   The binary form of each shape uses a different shape type for 2d and
   3d shapes.

   Nine shape type codes are defined.

4.9.1.  Point

   A point "shape" describes a single point with unknown uncertainty.
   It consists of a single set of coordinates.

   In a two-dimensional CRS, the coordinate includes two values; in a
   three-dimensional CRS, the coordinate includes three values.

4.9.1.1.  XML encoding

   A point is represented in GML using the following template:

   <gml:Point xmlns:gml="http://www.opengis.net/gml"
              srsName="$CRS-URN$">
     <gml:pos>$Coordinate-1 $Coordinate-2$ $Coordinate-3$</gml:pos>
   </gml:Point>

                            GML Point Template

   Where "$CRS-URN$" is replaced by a
   urn:ietf:params:geopriv:relative:2d or
   urn:ietf:params:geopriv:relative:3d and "$Coordinate-3$" is omitted
   if the CRS is two-dimensional.




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4.9.1.2.  TLV encoding

   The point shape is introduced by a TLV of 113 for a 2D point and 114
   for a 3D point.

   +------+------+
   | 113/4|Length|
   +------+------+------+------+
   |  Coordinate-1             |
   +------+------+------+------+
   |  Coordinate-2             |
   +------+------+------+------+
   |  (3D-only) Coordinate-3   |
   +------+------+------+------+

                              Point Encoding

4.9.2.  Circle or Sphere Shape

   A circle or sphere describes a single point with a single uncertainty
   value in meters.

   In a two-dimensional CRS, the coordinate includes two values and the
   resulting shape forms a circle.  In a three-dimensional CRS, the
   coordinate includes three values and the resulting shape forms a
   sphere.

4.9.2.1.  XML encoding

   A circle is represented in and converted from GML using the following
   template:

   <gs:Circle xmlns:gml="http://www.opengis.net/gml"
              xmlns:gs="http://www.opengis.net/pidflo/1.0"
              srsName="urn:ietf:params:geopriv:relative:2d">
     <gml:pos>$Coordinate-1 $Coordinate-2$</gml:pos>
     <gs:radius uom="urn:ogc:def:uom:EPSG::9001">
       $Radius$
     </gs:radius>
   </gs:Circle>

                            GML Circle Template

   A sphere is represented in and converted from GML using the following
   template:






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   <gs:Sphere xmlns:gml="http://www.opengis.net/gml"
              xmlns:gs="http://www.opengis.net/pidflo/1.0"
              srsName="urn:ietf:params:geopriv:relative:3d">
     <gml:pos>$Coordinate-1 $Coordinate-2$ $Coordinate-3$</gml:pos>
     <gs:radius uom="urn:ogc:def:uom:EPSG::9001">
       $Radius$
     </gs:radius>
   </gs:Sphere>

                            GML Sphere Template

4.9.2.2.  TLV encoding

   A circular shape is introduced by a type code of 115.  A spherical
   shape is introduced by a type code of 116.

   +------+------+
   | 115/6|Length|
   +------+------+------+------+
   |  Coordinate-1             |
   +------+------+------+------+
   |  Coordinate-2             |
   +------+------+------+------+
   |  (3D-only) Coordinate-3   |
   +------+------+------+------+
   |  Radius                   |
   +------+------+------+------+

                         Circle or Sphere Encoding

4.9.3.  Ellipse or Ellipsoid Shape

   A ellipse or ellipsoid describes a point with an elliptical or
   ellipsoidal uncertainty region.

   In a two-dimensional CRS, the coordinate includes two values, plus a
   semi-major axis, a semi-minor axis, a semi-major axis orientation
   (clockwise from North).  In a three-dimensional CRS, the coordinate
   includes three values and in addition to the two-dimensional values,
   an altitude uncertainty (semi-vertical) is added.

4.9.3.1.  XML encoding

   An ellipse is represented in and converted from GML using the
   following template:






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   <gs:Ellipse xmlns:gml="http://www.opengis.net/gml"
               xmlns:gs="http://www.opengis.net/pidflo/1.0"
               srsName="urn:ietf:params:geopriv:relative:2d">
     <gml:pos>$Coordinate-1 $Coordinate-2$</gml:pos>
     <gs:semiMajorAxis uom="urn:ogc:def:uom:EPSG::9001">
       $Semi-Major$
     </gs:semiMajorAxis>
     <gs:semiMinorAxis uom="urn:ogc:def:uom:EPSG::9001">
       $Semi-Minor$
     </gs:semiMinorAxis>
     <gs:orientation uom="urn:ogc:def:uom:EPSG::9102">
       $Orientation$
     </gs:orientation>
   </gs:Ellipse>

                           GML Ellipse Template

   An ellipsoid is represented in and converted from GML using the
   following template:

   <gs:Ellipsoid xmlns:gml="http://www.opengis.net/gml"
                 xmlns:gs="http://www.opengis.net/pidflo/1.0"
                 srsName="urn:ietf:params:geopriv:relative:3d">
     <gml:pos>$Coordinate-1 $Coordinate-2$ $Coordinate-3$</gml:pos>
     <gs:semiMajorAxis uom="urn:ogc:def:uom:EPSG::9001">
       $Semi-Major$
     </gs:semiMajorAxis>
     <gs:semiMinorAxis uom="urn:ogc:def:uom:EPSG::9001">
       $Semi-Minor$
     </gs:semiMinorAxis>
     <gs:verticalAxis uom="urn:ogc:def:uom:EPSG::9001">
       $Semi-Vertical$
     </gs:verticalAxis>
     <gs:orientation uom="urn:ogc:def:uom:EPSG::9102">
       $Orientation$
     </gs:orientation>
   </gs:Ellipsoid>

                          GML Ellipsoid Template

4.9.3.2.  TLV encoding

   An ellipse is introduced by a type code of 117 and an ellipsoid is
   introduced by a type code of 118.

   +------+------+
   | 117/8|Length|
   +------+------+------+------+



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   |  Coordinate-1             |
   +------+------+------+------+
   |  Coordinate-2             |
   +------+------+------+------+
   |  (3D-only) Coordinate-3   |
   +------+------+------+------+------+------+------+------+
   |  Semi-Major Axis          |  Semi-Minor Axis          |
   +------+------+------+------+------+------+------+------+
   |  Orientation              |  (3D) Semi-Vertical Axis  |
   +------+------+------+------+------+------+------+------+

                       Ellipse or Ellipsoid Encoding

4.9.4.  Polygon or Prism Shape

   A polygon or prism include a number of points that describe the outer
   boundary of an uncertainty region.  A prism also includes an altitude
   for each point and prism height.

   At least 3 points MUST be included in a polygon.  In order to
   interoperate with existing systems, an encoding SHOULD include 15 or
   fewer points, unless the recipient is known to support larger
   numbers.

4.9.4.1.  XML Encoding

   A polygon is represented in and converted from GML using the
   following template:

   <gml:Polygon xmlns:gml="http://www.opengis.net/gml"
                srsName="urn:ietf:params:geopriv:relative:2d">
     <gml:exterior>
       <gml:LinearRing>
         <gml:posList>
           $Coordinate1-1$ $Coordinate1-2$
           $Coordinate2-1$ $Coordinate2-2$
           $Coordinate3-1$ ...
           ...
           $CoordinateN-1$ $CoordinateN-2$
           $Coordinate1-1$ $Coordinate1-2$
         </gml:posList>
       </gml:LinearRing>
     </gml:exterior>
   </gml:Polygon>

                           GML Polygon Template





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   Alternatively, a series of "pos" elements can be used in place of the
   single "posList".  Each "pos" element contains two or three
   coordinate values.

   Note that the first point is repeated at the end of the sequence of
   coordinates and no explicit count of the number of points is
   provided.

   A GML polygon that includes altitude cannot be represented completely
   in binary.  When converting to the binary representation, a two
   dimensional CRS is used and altitude is removed from each coordinate.

   A prism is represented in and converted from GML using the following
   template:

   <gs:Prism xmlns:gml="http://www.opengis.net/gml"
             xmlns:gs="http://www.opengis.net/pidflo/1.0"
             srsName="urn:ietf:params:geopriv:relative:3d">
     <gs:base>
       <gml:Polygon>
         <gml:exterior>
           <gml:LinearRing>
             <gml:posList>
               $Coordinate1-1$ $Coordinate1-2$ $Coordinate1-3$
               $Coordinate2-1$ $Coordinate2-2$ $Coordinate2-3$
               $Coordinate2-1$ ... ...
               ...
               $CoordinateN-1$ $CoordinateN-2$ $CoordinateN-3$
               $Coordinate1-1$ $Coordinate1-2$ $Coordinate1-3$
             </gml:posList>
           </gml:LinearRing>
         </gml:exterior>
       </gml:Polygon>
     </gs:base>
     <gs:height uom="urn:ogc:def:uom:EPSG::9001">
       $Height$
     </gs:height>
   </gs:Prism>

                            GML Prism Template

   Alternatively, a series of "pos" elements can be used in place of the
   single "posList".  Each "pos" element contains three coordinate
   values.

4.9.4.2.  TLV Encoding





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   A polygon containing 2D points uses a type code of 119.  A polygon
   with 3D points uses a type code of 120.  A prism uses a type code of
   121.  The number of points can be inferred from the length of the
   TLV.

   +------+------+
   |119-21|Length|
   +------+------+------+------+
   |  (3D-only) Height         |
   +------+------+------+------+
   |  Coordinate1-1            |
   +------+------+------+------+
   |  Coordinate1-2            |
   +------+------+------+------+
   |  (3D-only) Coordinate1-3  |
   +------+------+------+------+
   |  Coordinate2-1            |
   +------+------+------+------+
    ...
   +------+------+------+------+
   |  CoordinateN-1            |
   +------+------+------+------+
   |  CoordinateN-2            |
   +------+------+------+------+
   |  (3D-only) CoordinateN-3  |
   +------+------+------+------+

                         Polygon or Prism Encoding

   Note that unlike the polygon representation in GML, the first and
   last points are not the same point in the TLV representation.  The
   duplicated point is removed from the binary form.

4.9.5.  Arc-Band Shape

   A arc-band describes a region constrained by a range of angles and
   distances from a predetermined point.  This shape can only be
   provided for a two-dimensional CRS.

   Distance and angular measures are defined in meters and degrees
   respectively.  Both are encoded as single precision floating point
   values.









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4.9.5.1.  XML encoding

   An arc-band is represented in and converted from GML using the
   following template:

   <gs:ArcBand xmlns:gml="http://www.opengis.net/gml"
               xmlns:gs="http://www.opengis.net/pidflo/1.0"
               srsName="urn:ietf:params:geopriv:relative:2d">
     <gml:pos>$Coordinate-1 $Coordinate-2$</gml:pos>
     <gs:innerRadius uom="urn:ogc:def:uom:EPSG::9001">
       $Inner-Radius$
     </gs:innerRadius>
     <gs:outerRadius uom="urn:ogc:def:uom:EPSG::9001">
       $Inner-Radius$
     </gs:outerRadius>
     <gs:startAngle uom="urn:ogc:def:uom:EPSG::9102">
      $Start-Angle$
     </gs:startAngle>
     <gs:openingAngle uom="urn:ogc:def:uom:EPSG::9102">
       $Opening-Angle$
     </gs:openingAngle>
   </gs:ArcBand>

                           GML Arc-Band Template

4.9.5.2.  TLV Encoding

   An arc-band is introduced by a type code of 122.

   +------+------+
   | 122  |Length|
   +------+------+------+------+
   |  Coordinate               |
   +------+------+------+------+
   |  Coordinate               |
   +------+------+------+------+------+------+------+------+
   |  Inner Radius             |  Outer Radius             |
   +------+------+------+------+------+------+------+------+
   |  Start Angle              |  Opening Angle            |
   +------+------+------+------+------+------+------+------+

                             Arc-Band Encoding









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4.10.  Dynamic Location TLVs

   Dynamic location elements use the definitions in [RFC5962].

4.10.1.  Orientation

   The orientation of the target is described using one or two angles.

   +------+------+
   | 123  |Length|
   +------+------+------+------+
   |         Angle             |
   +------+------+------+------+
   |   (Optional) Angle        |
   +------+------+------+------+

                         Dynamic Orientation TLVs

4.10.2.  Speed

   The speed of the target is a scalar value in meters per second.

   +------+------+
   | 124  |Length|
   +------+------+------+------+
   |         Speed             |
   +------+------+------+------+

                            Dynamic Speed TLVs

4.10.3.  Heading

   The heading, or direction of travel, is described using one or two
   angles.

   +------+------+
   | 125  |Length|
   +------+------+------+------+
   |         Angle             |
   +------+------+------+------+
   |   (Optional) Angle        |
   +------+------+------+------+

                           Dynamic Heading TLVs

4.11.  Secondary Map Metadata





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   The optional "map" URL can be used to provide a user of relative
   location with a visual reference for the location information.  This
   document does not describe how the recipient uses the map nor how it
   locates the reference or offset within the map.  Maps can be simple
   images, vector files, 2-D or 3-D geospatial databases, or any other
   form of representation understood by both the sender and recipient.

4.11.1.  Map URL

   In XML, the map is a <map> element defined within <relative-location>
   and contains the URL.  The URL is encoded as a UTF-8 encoded string.
   An "http:" or "https:" URL MUST be used unless the entity creating
   the PIDF-LO is able to ensure that authorized recipients of this data
   are able to use other URI schemes.  A "type" attribute MUST be
   present and specifies the kind of map the URL points to.  Map types
   are specified as mime media types as recorded in the IANA Media Types
   registry.  For example <map type="image/png">https://www.example.com/
   floorplans/123South/floor-2</map>.  In binary, the map type is a
   separate TLV from the map URL:

   +------+------+------+------+------+--  --+------+
   |  126 |Length|   Map Media Type         ...
   +------+------+------+------+------+--  --+------+
   |  127 |Length|   Map Image URL          ...
   +------+------+------+------+------+--  --+------+

                               Map URL TLVs

4.11.2.  Map Coordinate Reference System

   The CRS used by the map depends on the type of map.  For example, a
   map described by a 3-D geometric model of the building may contain a
   complete CRS description in it.  For some kinds of maps, typically
   described as images, the CRS used within the map must define the
   following:

   o  The CRS origin

   o  The CRS axes used and their orientation

   o  The unit of measure used

   This document provides elements that allow for a mapping between the
   local coordinate reference system used for the relative location and
   the coordinate reference system used for the map where they are not
   the same.





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4.11.2.1.  Map Reference Point Offset

   This optional element identifies the coordinates of the reference
   point as it appears in the map.  This value is measured in a map-type
   dependent manner, using the coordinate system of the map.

   For image maps, coordinates start from the upper left corner and
   coordinates are first counted by column with positive values to the
   right; then rows are counted with positive values toward the bottom
   of the image.  For such an image, the first item is columns, the
   second rows and any third value applies to any third dimension used
   in the image coordinate space.

   The <offset> element contains 2 (or 3) coordinates similar to a GML
   "pos", For example:

     <offset> 2670.0 1124.0 1022.0</offset>

                      Map Reference Point Example XML

   +------+------+
   | 128  |Length|
   +------+------+------+------+
   |  Coordinate-1             |
   +------+------+------+------+
   |  Coordinate-2             |
   +------+------+------+------+
   |  (3D-only) Coordinate-3   |
   +------+------+------+------+

                    Map Reference Point Coordinates TLV

   If omitted, a value containing all zeros is assumed.  If the
   coordinates provided contain fewer values than are needed, the first
   value from the set is applied in place of any missing values.

4.11.2.2.  Map Orientation

   The map orientation includes the orientation of the map direction in
   relation to the Earth.  Map orientation is expressed relative to the
   orientation of the relative coordinate system.  This means that map
   orientation with respect to WGS84 North is the sum of the orientation
   field, plus any orientation included in a dynamic portion of the
   reference location.  Both values default to zero if no value is
   specified.

   This type uses a single precision floating point value of degrees
   relative to North.



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   In XML, the <orientation> element contains a single floating point
   value, example <orientation>67.00</orientation>.  In TLV form:

   +------+------+------+------+------+------+
   |  129 |Length|  Angle                    |
   +------+------+------+------+------+------+

                            Map Orientation TLV

4.11.2.3.  Map Scale

   The optional map scale describes the relationship between the units
   of measure used in the map, relative to the meters unit used in the
   relative coordinate system.

   This type uses a sequence of IEEE 754 [IEEE.754] single precision
   floating point values to represent scale as a sequence of numeric
   values.  The units of these values are dependent on the type of map,
   and could for example be pixels per meter for an image.

   A scaling factor is provided for each axis in the coordinate system.
   For a two-dimensional coordinate system, two values are included to
   allow for different scaling along the x and y axes independently.
   For a three-dimensional coordinate system, three values are specified
   for the x, y and z axes.  Decoders can determine the number of
   scaling factors by examining the length field.

   Alternatively, a single scaling value MAY be used to apply the same
   scaling factor to all coordinate components.

   Images that use a rows/columns coordinate system often use a left-
   handed coordinate system.  A negative value for the y/rows-axis
   scaling value can be used to account for any change in direction
   between the y-axis used in the relative coordinate system and the
   rows axis of the image coordinate system.

   In XML, the <scale> element may contain the single scale value, or
   may contain 2 (or 3) values similar to a GML "pos" with separate
   scale values.  In TLV form:

   +------+------+------+------+------+
   |  130 |Length|  Scales       ...
   +------+------+------+------+------+

                               Map Scale TLV

4.11.3.  Map Example




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   An example of expressing a map is:

        <rel:map>
          <rel:url type="image/jpeg">
            http://example.com/map.jpg
          </rel:url>
          <rel:offset>200 210</rel:offset>
          <rel:orientation>68</rel:orientation>
          <rel:scale>2.90 -2.90</rel:scale>
        </rel:map>

                                Map Example

5.  Examples

5.1.  Civic PIDF with Polygon Offset

    <presence xmlns="urn:ietf:params:xml:ns:pidf"
              xmlns:dm="urn:ietf:params:xml:ns:pidf:data-model"
              xmlns:gp="urn:ietf:params:xml:ns:pidf:geopriv10"
              xmlns:ca="urn:ietf:params:xml:ns:pidf:geopriv10:civicAddr"
              xmlns:rel="urn:ietf:params:xml:ns:pidf:geopriv10:relative"
              xmlns:gml="http://www.opengis.net/gml"
              xmlns:gs="http://www.opengis.net/pidflo/1.0"
              entity="pres:ness@example.com">
      <dm:device id="nesspc-1">
        <gp:geopriv>
          <gp:location-info>
            <ca:civicAddress xml:lang="en-AU">
              <ca:country>AU</ca:country>
              <ca:A1>NSW</ca:A1>
              <ca:A3>Wollongong</ca:A3>
              <ca:A4>North Wollongong</ca:A4>
              <ca:RD>Flinders</ca:RD>
              <ca:STS>Street</ca:STS>
              <ca:HNO>123</ca:HNO>
            </ca:civicAddress>
            <rel:relative-location>
              <rel:reference>
                <ca:civicAddress xml:lang="en-AU">
                  <ca:INT N="Building">A</ca:INT>
                  <ca:INT N="Level">I</ca:INT>
                  <ca:INT N="Suite">113</ca:INT>
                  <ca:INT N="Door" R="A">Front</ca:INT>
                </ca:civicAddress>
              </rel:reference>
              <rel:offset>
                 <gml:Polygon xmlns:gml="http://www.opengis.net/gml"



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                      srsName="urn:ietf:params:geopriv:relative:2d">
                   <gml:exterior>
                     <gml:LinearRing>
                       <gml:pos>433.0 -734.0</gml:pos> <!--A-->
                       <gml:pos>431.0 -733.0</gml:pos> <!--F-->
                       <gml:pos>431.0 -732.0</gml:pos> <!--E-->
                       <gml:pos>433.0 -731.0</gml:pos> <!--D-->
                       <gml:pos>434.0 -732.0</gml:pos> <!--C-->
                       <gml:pos>434.0 -733.0</gml:pos> <!--B-->
                       <gml:pos>433.0 -734.0</gml:pos> <!--A-->
                     </gml:LinearRing>
                   </gml:exterior>
                </gml:Polygon>
              </rel:offset>
            </rel:relative-location>
          </gp:location-info>
         <gp:usage-rules/>
          <gp:method>GPS</gp:method>
        </gp:geopriv>
        <dm:deviceID>mac:1234567890ab</dm:deviceID>
        <dm:timestamp>2007-06-22T20:57:29Z</dm:timestamp>
      </dm:device>
    </presence>


5.2.  Geo PIDF with Circle Offset

   <?xml version="1.0" encoding="UTF-8"?>
       <presence xmlns="urn:ietf:params:xml:ns:pidf"
            xmlns:dm="urn:ietf:params:xml:ns:pidf:data-model"
            xmlns:gp="urn:ietf:params:xml:ns:pidf:geopriv10"
            xmlns:rel="urn:ietf:params:xml:ns:pidf:geopriv10:relative"
            xmlns:gml="http://www.opengis.net/gml"
            xmlns:gs="http://www.opengis.net/pidflo/1.0"
            entity="pres:point2d@example.com">
         <dm:device id="point2d">
           <gp:geopriv>
             <gp:location-info>
               <gs:Circle srsName="urn:ogc:def:crs:EPSG::4326">
                 <gml:pos>-34.407 150.883</gml:pos>
                 <gml:radius uom="urn:ogc:def:uom:EPSG::9001">
                        50.0
                 </gml:radius>
               </gs:Circle>
               <rel:relative-location>
                 <rel:reference>
                   <gml:Point srsName="urn:ogc:def:crs:EPSG::4326">
                     <gml:pos>-34.407 150.883</gml:pos>



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                   </gml:Point>
                 </rel:reference>
                 <rel:offset>
                   <gml:Circle xmlns:gml="http://www.opengis.net/gml"
                         srsName="urn:ietf:params:geopriv:relative:2d">
                       <gml:pos>500.0 750.0</gml:pos>
                       <gml:radius uom="urn:ogc:def:uom:EPSG::9001">
                          5.0
                        </gml:radius>
                  </gml:Circle>
                </rel:offset>
                <rel:map>
                   <rel:urltype="image/png">
                     https://www.example.com/flrpln/123South/flr-2
                     </rel:url>
                   <rel:offset> 2670.0 1124.0 1022.0</rel:offset>
                   <rel:orientation>67.00</rel:orientation>
                   <rel:scale>10</rel:scale>
                </rel:map>
               </rel:relative-location>
             </gp:location-info>
             <gp:usage-rules/>
             <gp:method>Wiremap</gp:method>
           </gp:geopriv>
           <dm:deviceID>mac:1234567890ab</dm:deviceID>
           <dm:timestamp>2007-06-22T20:57:29Z</dm:timestamp>
         </dm:device>
        </gp:geopriv>
       </status>
       <timestamp>2003-06-22T20:57:29Z</timestamp>
      </tuple>
     </presence>


5.3.  Civic TLV with Point Offset

        +--------+-------------------------------------------------+
        | Type   | Value                                           |
        +--------+-------------------------------------------------+
        | 0      | en                                              |
        |        |                                                 |
        | 1      | IL                                              |
        |        |                                                 |
        | 3      | Chicago                                         |
        |        |                                                 |
        | 34     | Wacker                                          |
        |        |                                                 |
        | 18     | Drive                                           |



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        |        |                                                 |
        | 19     | 3400                                            |
        |        |                                                 |
        | 112    | Reference                                       |
        |        |                                                 |
        | 25     | Building A                                      |
        |        |                                                 |
        | 27     | Floor 6                                         |
        |        |                                                 |
        | 26     | Suite 213                                       |
        |        |                                                 |
        | 28     | Reception Area                                  |
        |        |                                                 |
        | 115    | 100 70                                          |
        |        |                                                 |
        | 126    | image/png                                       |
        |        |                                                 |
        | 127    | http://maps.example.com/3400Wacker/A6           |
        |        |                                                 |
        | 128    | 0.0 4120.0                                      |
        |        |                                                 |
        | 129    | 113.0                                           |
        |        |                                                 |
        | 130    | 10.6                                            |
        +--------+-------------------------------------------------+


6.  Schema Definition

   <?xml version="1.0"?>
   <xs:schema
       xmlns:rel="urn:ietf:params:xml:ns:pidf:geopriv10:relative"
       xmlns:xs="http://www.w3.org/2001/XMLSchema"
       xmlns:gml="http://www.opengis.net/gml"
       targetNamespace="urn:ietf:params:xml:ns:pidf:geopriv10:relative"
       elementFormDefault="qualified"
       attributeFormDefault="unqualified">

     <!-- [[NOTE TO RFC-EDITOR: Please replace all instances of the URL
          'http://ietf.org/rfc/rfcXXXX.txt' with the URL of published
          document and remove this note.]] -->

     <xs:annotation>
       <xs:appinfo
           source="urn:ietf:params:xml:schema:pidf:geopriv10:relative">
         Relative Location for PIDF-LO
       </xs:appinfo>
       <xs:documentation source="http://ietf.org/rfc/rfcXXXX.txt">



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         This schema defines a location representation that allows for
         the description of locations that are relative to another.
         An optional map reference is also defined.
       </xs:documentation>
     </xs:annotation>

     <xs:import namespace="http://www.opengis.net/gml"/>

     <xs:element name="relative-location" type="rel:relativeType"/>

     <xs:complexType name="relativeType">
       <xs:complexContent>
         <xs:restriction base="xs:anyType">
           <xs:sequence>
             <xs:element name="reference" type="rel:referenceType"/>
             <xs:element name="offset" type="rel:offsetType"/>
             <xs:any namespace="##any" processContents="lax"
                     minOccurs="0" maxOccurs="unbounded"/>
           </xs:sequence>
           <xs:anyAttribute namespace="##other" processContents="lax"/>
         </xs:restriction>
       </xs:complexContent>
     </xs:complexType>

     <xs:complexType name="referenceType">
       <xs:complexContent>
         <xs:restriction base="xs:anyType">
           <xs:sequence>
             <xs:any namespace="##other" processContents="lax"
                     minOccurs="0" maxOccurs="unbounded"/>
           </xs:sequence>
         </xs:restriction>
       </xs:complexContent>
     </xs:complexType>

     <xs:complexType name="offsetType">
       <xs:complexContent>
         <xs:restriction base="xs:anyType">
           <xs:sequence>
             <xs:element ref="gml:_Geometry"/>
             <xs:any namespace="##other" processContents="lax"
                     minOccurs="0" maxOccurs="unbounded"/>
           </xs:sequence>
         </xs:restriction>
       </xs:complexContent>
     </xs:complexType>

     <xs:element name="map" type="rel:mapType"/>



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     <xs:complexType name="mapType">
       <xs:complexContent>
         <xs:restriction base="xs:anyType">
           <xs:sequence>
             <xs:element name="url" type="rel:mapUrlType"/>
             <xs:element name="offset" type="rel:doubleList"
                         minOccurs="0"/>
             <xs:element name="orientation" type="rel:doubleList"
                         minOccurs="0"/>
             <xs:element name="scale" type="rel:doubleList"
                         minOccurs="0"/>
           </xs:sequence>
         </xs:restriction>
       </xs:complexContent>
     </xs:complexType>

     <xs:complexType name="mapUrlType">
       <xs:simpleContent>
         <xs:extension base="xs:anyURI">
           <xs:attribute name="type" type="rel:mimeType"
                         default="application/octet-stream"/>
         </xs:extension>
       </xs:simpleContent>
     </xs:complexType>

     <xs:simpleType name="mimeType">
       <xs:restriction base="xs:token">
         <xs:pattern value="[!#$%&amp;'\*\+\-\.\dA-Z^_`a-z\|~]+
         /[!#$%&amp;'\*\+\-\.\dA-Z^_`a-z\|~]+([\t ]*;([\t ])*[!#$%&amp;
         '\*\+\-\.\dA-Z^_`a-z\|~]+=([!#$%&amp;'\*\+\-\.\dA-Z^_`a-z\|~]+|
         &quot;([!#-\[\]-~]|[\t ]*|\\[\t !-~])*&quot;))*"/>
       </xs:restriction>
     </xs:simpleType>

     <xs:simpleType name="doubleList">
       <xs:list itemType="xs:double"/>
     </xs:simpleType>

   </xs:schema>

                       xml schema relative-location

7.  Security Considerations

   This document describes a data format.  To a large extent, security
   properties of this depend on how this data is used.





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   Privacy for location data is typically important.  Adding relative
   location may increase the precision of the location, but does not
   otherwise alter its privacy considerations, which are discussed in
   [RFC4119]

   The fractional bits in IEEE 754 [IEEE.754] floating point values can
   be used as a covert channel.  For values of either zero or infinity,
   non-zero fraction bits could be used to convey information.  If the
   presence of covert channels is not desired then the fractional bits
   MUST be set to zero.  There is no need to represent NaN (not a
   number) in this encoding.

8.  IANA Considerations

8.1.  Relative Location Registry

   This document creates a new registry called 'Relative Location
   Parameters'.  As defined in [RFC5226], this registry operates under
   "IETF Review" rules.

   The content of this registry includes:

   Relative Location Code: Numeric identifier, assigned by IANA.

   Brief description: Short description identifying the meaning of the
   element.

   Reference to published specification: A stable reference to an RFC
   which describes the value in sufficient detail so that
   interoperability between independent implementations is possible.

   Values requested to be assigned into this registry MUST NOT conflict
   with values assigned in the CAtypes registry or vice versa, unless
   the IANA considerations section for the new value explicitly
   overrides this prohibition and the document defining the value
   describes how conflicting TLV codes will be interpreted by
   implementations.

   The values defined are:

   +--------+----------------------------------------+-----------+
   | RLtype | description                            | Reference |
   +--------+-------+--------------------------------+-----------+
   | 111    | relative location reference            | this RFC  |
   | 113    | relative location shape 2D point       | this RFC  |
   | 114    | relative location shape 3D point       | this RFC  |
   | 115    | relative location shape circular       | this RFC  |
   | 116    | relative location shape spherical      | this RFC  |



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   | 117    | relative location shape elliptical     | this RFC  |
   | 118    | relative location shape ellipsoid      | this RFC  |
   | 119    | relative location shape 2D polygon     | this RFC  |
   | 120    | relative location shape 3D polygon     | this RFC  |
   | 121    | relative location shape prism          | this RFC  |
   | 122    | relative location shape arc-band       | this RFC  |
   | 123    | relative location dynamic orientation  | this RFC  |
   | 124    | relative location dynamic speed        | this RFC  |
   | 125    | relative location dynamic heading      | this RFC  |
   | 126    | relative location map type             | this RFC  |
   | 127    | relative location map URI              | this RFC  |
   | 128    | relative location map coordinates      | this RFC  |
   | 129    | relative location map angle            | this RFC  |
   | 130    | relative location map scale            | this RFC  |
   +--------+-------+--------------------------------+-----------+


8.2.  URN Sub-Namespace Registration

   This document registers a new XML namespace, as per the guidelines in
   [RFC3688]).






























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      URI:  urn:ietf:params:xml:ns:pidf:geopriv10:relative

      Registrant Contact:IETF, GEOPRIV working group (geopriv@ietf.org),
         Martin Thomson (martin.thomson@skype.net).

      XML:

       BEGIN
         <?xml version="1.0"?>
         <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
              "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
         <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
           <head>
             <title>GEOPRIV Relative Location</title>
           </head>
           <body>
             <h1>Format for representing relative location</h1>
             <h2>urn:ietf:params:xml:ns:pidf:geopriv10:relative</h2>
             <p>See <a href="http://www.rfc-editor.org/rfc/rfcXXXX.txt">
                    RFCXXXX</a>.</p>
           </body>
         </html>
     <!-- [[NOTE TO RFC-EDITOR: Please replace all instances of RFCXXXX
          with the number of the published
          document and remove this note.]] -->
          END


8.3.  XML Schema Registration

   This section registers an XML schema as per the procedures in
   [RFC3688].


      URI:  urn:ietf:params:xml:schema:pidf:geopriv10:relativeLocation

      Registrant Contact:IETF, GEOPRIV working group (geopriv@ietf.org),
         Martin Thomson (martin.thomson@skype.net).

         The XML for this schema is the entirety of Section 6
         of this document.










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8.4.  CRS public identifier registration

   This section registers two public identifiers as per the procedures
   in [RFC3688].


      URI:  urn:ietf:params:xml:ns:pidf:geopriv10:relative:2d

      Registrant Contact:IETF, GEOPRIV working group (geopriv@ietf.org),
         Martin Thomson (martin.thomson@skype.net).

      XML:

        BEGIN
          <?xml version="1.0"?>
          <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
              "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
          <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
            <head>
              <title>GEOPRIV Relative Location 2d CRS</title>
            </head>
            <body>
              <h1>Identifier for a 2D CRS in relative location</h1>
              <h2>urn:ietf:params:xml:ns:pidf:geopriv10:relative:2d</h2>
              <p>See <a href="http://www.rfc-editor.org/rfc/rfcXXXX.txt">
                    RFCXXXX</a>.</p>
            </body>
         </html>
     <!-- [[NOTE TO RFC-EDITOR: Please replace all instances of RFCXXXX
          with the number of the published document
          and remove this note.]] -->
       END

       URI:  urn:ietf:params:xml:ns:pidf:geopriv10:relative:3d

       Registrant Contact:IETF, GEOPRIV working group (geopriv@ietf.org)
         Martin Thomson (martin.thomson@skype.net).

      XML:

        BEGIN
          <?xml version="1.0"?>
          <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
              "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
          <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
            <head>
              <title>GEOPRIV Relative Location 3d CRS</title>
            </head>



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            <body>
              <h1>Identifier for a 3D CRS in relative location</h1>
              <h2>urn:ietf:params:xml:ns:pidf:geopriv10:relative:3d</h2>
              <p>See <a href="http://www.rfc-editor.org/rfc/rfcXXXX.txt">
                    RFCXXXX</a>.</p>
            </body>
         </html>
     <!-- [[NOTE TO RFC-EDITOR: Please replace all instances of RFCXXXX
          with the number of the published
          document and remove this note.]] -->
          END


8.5.  CAtype Registration

   This section adds a new entry to the CAtype registry defined by
   [RFC6848].

   Namespace URI:  urn:ietf:params:xml:ns:pidf:geopriv10:relative

   Local Name:  REL

   Description:  Relative location from a reference point

   Contact:  The IESG (iesg@ietf.org); the GEOPRIV working group
      (geopriv@ietf.org).

   Specification:  RFCXXXX

   Schema:  urn:ietf:params:xml:schema:pidf:geopriv10:relativeLocation

   Type:  A

9.  Acknowledgements

   This is the product of a design team on relative location.  Besides
   the authors, this team included: Marc Linsner, James Polk, and James
   Winterbottom.

10.  References

10.1.  Normative References

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

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



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   [RFC4776]  Schulzrinne, H., "Dynamic Host Configuration Protocol
              (DHCPv4 and DHCPv6) Option for Civic Addresses
              Configuration Information", RFC 4776, November 2006.

   [RFC5139]  Thomson, M. and J. Winterbottom, "Revised Civic Location
              Format for Presence Information Data Format Location
              Object (PIDF-LO)", RFC 5139, February 2008.

   [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", BCP 26, RFC 5226,
              May 2008.

   [RFC5491]  Winterbottom, J., Thomson, M., and H. Tschofenig, "GEOPRIV
              Presence Information Data Format Location Object (PIDF-LO)
              Usage Clarification, Considerations, and Recommendations",
              RFC 5491, March 2009.

   [RFC5962]  Schulzrinne, H., Singh, V., Tschofenig, H., and M.
              Thomson, "Dynamic Extensions to the Presence Information
              Data Format Location Object (PIDF-LO)", RFC 5962,
              September 2010.

   [RFC6225]  Polk, J., Linsner, M., Thomson, M., and B. Aboba, "Dynamic
              Host Configuration Protocol Options for Coordinate-Based
              Location Configuration Information", RFC 6225, July 2011.

   [RFC6848]  Winterbottom, J., Thomson, M., Barnes, R., Rosen, B., and
              R. George, "Specifying Civic Address Extensions in the
              Presence Information Data Format Location Object (PIDF-
              LO)", RFC 6848, January 2013.

   [OGC.GML-3.1.1]
              Cox, S., Daisey, P., Lake, R., Portele, C., and A.
              Whiteside, "Geographic information - Geography Markup
              Language (GML)", OpenGIS 03-105r1, April 2004, <http://
              portal.opengeospatial.org/files/?artifact_id=4700>.

   [OGC.GeoShape]
              Thomson, M. and C. Reed, "GML 3.1.1 PIDF-LO Shape
              Application Schema for use by the Internet Engineering
              Task Force (IETF)", OGC Best Practice 06-142r1, Version:
              1.0, April 2007.

   [IEEE.754]
              IEEE, "IEEE Standard for Binary Floating-Point
              Arithmetic", IEEE Standard 754-1985, January 2003.

   [Clinger1990]



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              Clinger, W., "How to Read Floating Point Numbers
              Accurately", Proceedings of Conference on Programming
              Language Design and Implementation pp. 92-101, 1990, <ftp:
              //ftp.ccs.neu.edu/pub/people/will/howtoread.ps>.

10.2.  Informative References

   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              January 2004.

   [WGS84]    US National Imagery and Mapping Agency , ""Department of
              Defense (DoD) World Geodetic System 1984 (WGS 84), Third
              Edition"", NIMA TR8350.2, January 2000.

Authors' Addresses

   Martin Thomson
   Microsoft
   3210 Porter Drive
   Palo Alto, CA  94304
   US

   Phone: +1 650-353-1925
   EMail: martin.thomson@skype.net


   Brian Rosen
   Neustar
   470 Conrad Dr
   Mars, PA  16046
   US

   EMail: br@brianrosen.net


   Dorothy Stanley
   Aruba Networks
   1322 Crossman Ave
   Sunnyvale, CA  94089
   US

   EMail: dstanley@arubanetworks.com









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   Gabor Bajko
   Nokia
   323 Fairchild Drive
   Mountain View, CA  94043
   US

   EMail: gabor.bajko@nokia.com


   Allan Thomson
   Cisco Systems, Inc.
   170 West Tasman Drive
   San Jose, CA  95134
   US

   EMail: althomso@cisco.com


































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