RFC 5491 - GEOPRIV Presence Information Data Format Location Object (PIDF-LO) Usage Clarification, Considerations, and Recommendations

<!DOCTYPE html> <html data-bs-theme="auto" lang="en"> <head> <meta charset="utf-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <title> RFC 5491 - GEOPRIV Presence Information Data Format Location Object (PIDF-LO) Usage Clarification, Considerations, and Recommendations </title> <meta name="viewport" content="width=device-width, initial-scale=1"> <link href="https://static.ietf.org/fonts/inter/import.css" rel="stylesheet"> <link href="https://static.ietf.org/fonts/noto-sans-mono/import.css" rel="stylesheet"> <link rel="stylesheet" href="https://static.ietf.org/dt/12.28.2/ietf/css/document_html_referenced.css"> <script type="module" crossorigin="" src="https://static.ietf.org/dt/12.28.2/assets/embedded-e653257c.js"></script> <link href="https://static.ietf.org/dt/12.28.2/assets/create-pinia-singleton-091c62b7.js" type="text/javascript" crossorigin="anonymous" rel="modulepreload" as="script" /> <link href="https://static.ietf.org/dt/12.28.2/assets/Scrollbar-7de50899.js" type="text/javascript" crossorigin="anonymous" rel="modulepreload" as="script" /> <script src="https://static.ietf.org/dt/12.28.2/ietf/js/document_html.js"></script> <script src="https://static.ietf.org/dt/12.28.2/ietf/js/theme.js"></script> <link rel="alternate" type="application/atom+xml" title="Document changes" href="/feed/document-changes/rfc5491/"> <meta name="description" content="GEOPRIV Presence Information Data Format Location Object (PIDF-LO) Usage Clarification, Considerations, and Recommendations (RFC 5491, )" > <link rel="apple-touch-icon" sizes="180x180" href="https://static.ietf.org/dt/12.28.2/ietf/images/ietf-logo-nor-180.png"> <link rel="icon" sizes="32x32" href="https://static.ietf.org/dt/12.28.2/ietf/images/ietf-logo-nor-32.png"> <link rel="icon" sizes="16x16" href="https://static.ietf.org/dt/12.28.2/ietf/images/ietf-logo-nor-16.png"> <link rel="manifest" href="/site.webmanifest"> <link rel="mask-icon" href="https://static.ietf.org/dt/12.28.2/ietf/images/ietf-logo-nor-mask.svg" color="#ffffff"> <meta name="msapplication-TileColor" content="#ffffff"> <meta name="theme-color" content="#ffffff"> <meta property="og:title" content="RFC 5491: GEOPRIV Presence Information Data Format Location Object (PIDF-LO) Usage Clarification, Considerations, and Recommendations"> <meta property="og:url" content="https://datatracker.ietf.org/doc/html/rfc5491"> <link rel="canonical" href="https://datatracker.ietf.org/doc/html/rfc5491"> <meta property="og:site_name" content="IETF Datatracker"> <meta property="og:description" content="The Presence Information Data Format Location Object (PIDF-LO) specification provides a flexible and versatile means to represent location information. There are, however, circumstances that arise when information needs to be constrained in how it is represented. In these circumstances, the range of options that need to be implemented are reduced. There is growing interest in being able to use location information contained in a PIDF-LO for routing applications. To allow successful interoperability between applications, location information needs to be normative and more tightly constrained than is currently specified in RFC 4119 (PIDF-LO). This document makes recommendations on how to constrain, represent, and interpret locations in a PIDF-LO. It further recommends a subset of Geography Markup Language (GML) 3.1.1 that is mandatory to implement by applications involved in location-based routing. [STANDARDS-TRACK]"> <meta property="og:type" content="article"> <meta property="og:image" content="https://static.ietf.org/dt/12.28.2/ietf/images/ietf-logo-card.png"> <meta property="og:image:alt" content="Logo of the IETF"> <meta property="article:section" content="IETF - Internet Engineering Task Force"> <meta property="og:image:type" content="image/png"> <meta property="og:image:width" content="1200"> <meta property="og:image:height" content="630"> <meta name="twitter:card" content="summary_large_image"> <meta property="article:author" content="Martin Thomson"> <meta property="article:author" content="James Winterbottom"> <meta property="article:author" content="Hannes Tschofenig"> <style> .diff-form .select2-selection__rendered { direction: rtl; text-align: left; } </style> </head> <body> <noscript><iframe class="status" title="Site status" src="/status/latest"></iframe></noscript> <div class="vue-embed" data-component="Status"></div> <div class="btn-toolbar sidebar-toolbar position-fixed top-0 end-0 m-2 m-lg-3 d-print-none"> <div class="dropdown"> <button class="btn btn-outline-secondary btn-sm me-1 dropdown-toggle d-flex align-items-center" id="bd-theme" type="button" aria-expanded="false" data-bs-toggle="dropdown" aria-label="Toggle theme"> <i class="theme-icon-active bi bi-circle-half"></i> </button> <ul class="dropdown-menu" aria-labelledby="bd-theme"> <li> <button type="button" class="dropdown-item d-flex align-items-center" data-bs-theme-value="light" aria-pressed="false"> <i class="me-2 opacity-50 theme-icon bi bi-sun-fill"></i> Light<i class="bi bi-check2 ms-auto d-none"></i> </button> </li> <li> <button type="button" class="dropdown-item d-flex align-items-center" data-bs-theme-value="dark" aria-pressed="false"> <i class="me-2 opacity-50 theme-icon bi bi-moon-stars-fill"></i> Dark<i class="bi bi-check2 ms-auto d-none"></i> </button> </li> <li> <button type="button" class="dropdown-item d-flex align-items-center active" data-bs-theme-value="auto" aria-pressed="true"> <i class="me-2 opacity-50 theme-icon bi bi-circle-half"></i> Auto<i class="bi bi-check2 ms-auto d-none"></i> </button> </li> </ul> </div> <button class="btn btn-outline-secondary btn-sm sidebar-toggle" type="button" data-bs-toggle="collapse" data-bs-target="#sidebar" aria-expanded="true" aria-controls="sidebar" aria-label="Toggle metadata sidebar" title="Toggle metadata sidebar"> <i class="bi bi-arrow-bar-left sidebar-shown"></i> <i class="bi bi-arrow-bar-right sidebar-collapsed"></i> </button> </div> <nav class="navbar bg-light-subtle px-1 fixed-top d-print-none d-md-none"> <a class="nav-link ps-1" href="/doc/rfc5491/"> RFC 5491 <br class="d-sm-none"> <span class="ms-sm-3 badge rounded-pill badge-ps"> Proposed Standard </span> </a> <button class="navbar-toggler p-1" type="button" data-bs-toggle="collapse" data-bs-target="#docinfo-collapse" aria-controls="docinfo-collapse" aria-expanded="false" aria-label="Show document information"> <span class="navbar-toggler-icon small"></span> </button> <div class="navbar-nav navbar-nav-scroll overscroll-none collapse pt-1" id="docinfo-collapse"> <div class="bg-light-subtle p-0"> <table class="table table-sm table-borderless small"> <tbody class="meta align-top"> <tr> <th scope="row"></th> <th scope="row">Title</th> <td class="edit"></td> <td>GEOPRIV Presence Information Data Format Location Object (PIDF-LO) Usage Clarification, Considerations, and Recommendations</td> </tr> </tbody> <tbody class="meta align-top "> <tr> <th scope="row">Document</th> <th scope="row">Document type</th> <td class="edit"></td> <td> <span class="text-success">RFC - Proposed Standard </span> <br>March 2009 <br> <a class="btn btn-primary btn-sm my-1" href="https://www.rfc-editor.org/errata_search.php?rfc=5491" title="Click to view errata." rel="nofollow"> View errata </a> <a class="btn btn-sm btn-warning" title="Click to report an error in the document." href="https://www.rfc-editor.org/errata.php#reportnew" target="_blank"> Report errata </a> <div>Updated by <a href="/doc/html/rfc7459" title="Representation of Uncertainty and Confidence in the Presence Information Data Format Location Object (PIDF-LO)">RFC 7459</a></div> <div>Updates <a href="/doc/html/rfc4119" title="A Presence-based GEOPRIV Location Object Format">RFC 4119</a></div> <div> Was <a href="/doc/draft-ietf-geopriv-pdif-lo-profile/14/">draft-ietf-geopriv-pdif-lo-profile</a> (<a href="/wg/geopriv/about/">geopriv WG</a>) </div> </td> </tr> <tr> <td></td> <th scope="row">Select version</th> <td class="edit"></td> <td> <ul class="revision-list pagination pagination-sm text-center flex-wrap my-0"> <li class="page-item"> <a class="page-link" href="/doc/html/draft-ietf-geopriv-pdif-lo-profile-14" rel="nofollow"> 14 </a> </li> <li class="page-item rfc active"> <a class="page-link" href="/doc/html/rfc5491"> RFC 5491 </a> </li> </ul> </td> </tr> <tr> <td></td> <th scope="row">Compare versions</th> <td class="edit"></td> <td> <form class="form-horizontal diff-form" action="https://author-tools.ietf.org/iddiff" method="get" target="_blank"> <select class="form-select form-select-sm mb-1 select2-field" data-max-entries="1" data-width="resolve" data-allow-clear="false" data-minimum-input-length="0" aria-label="From revision" name="url1"> <option value="rfc5491"> RFC 5491 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-14" selected> draft-ietf-geopriv-pdif-lo-profile-14 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-13"> draft-ietf-geopriv-pdif-lo-profile-13 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-12"> draft-ietf-geopriv-pdif-lo-profile-12 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-11"> draft-ietf-geopriv-pdif-lo-profile-11 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-10"> draft-ietf-geopriv-pdif-lo-profile-10 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-09"> draft-ietf-geopriv-pdif-lo-profile-09 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-08"> draft-ietf-geopriv-pdif-lo-profile-08 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-07"> draft-ietf-geopriv-pdif-lo-profile-07 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-06"> draft-ietf-geopriv-pdif-lo-profile-06 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-05"> draft-ietf-geopriv-pdif-lo-profile-05 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-04"> draft-ietf-geopriv-pdif-lo-profile-04 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-03"> draft-ietf-geopriv-pdif-lo-profile-03 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-02"> draft-ietf-geopriv-pdif-lo-profile-02 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-01"> draft-ietf-geopriv-pdif-lo-profile-01 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-00"> draft-ietf-geopriv-pdif-lo-profile-00 </option> </select> <select class="form-select form-select-sm mb-1 select2-field" data-max-entries="1" data-width="resolve" data-allow-clear="false" data-minimum-input-length="0" aria-label="To revision" name="url2"> <option value="rfc5491" selected> RFC 5491 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-14"> draft-ietf-geopriv-pdif-lo-profile-14 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-13"> draft-ietf-geopriv-pdif-lo-profile-13 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-12"> draft-ietf-geopriv-pdif-lo-profile-12 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-11"> draft-ietf-geopriv-pdif-lo-profile-11 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-10"> draft-ietf-geopriv-pdif-lo-profile-10 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-09"> draft-ietf-geopriv-pdif-lo-profile-09 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-08"> draft-ietf-geopriv-pdif-lo-profile-08 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-07"> draft-ietf-geopriv-pdif-lo-profile-07 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-06"> draft-ietf-geopriv-pdif-lo-profile-06 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-05"> draft-ietf-geopriv-pdif-lo-profile-05 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-04"> draft-ietf-geopriv-pdif-lo-profile-04 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-03"> draft-ietf-geopriv-pdif-lo-profile-03 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-02"> draft-ietf-geopriv-pdif-lo-profile-02 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-01"> draft-ietf-geopriv-pdif-lo-profile-01 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-00"> draft-ietf-geopriv-pdif-lo-profile-00 </option> </select> <button type="submit" class="btn btn-primary btn-sm" value="--html" name="difftype"> Side-by-side </button> <button type="submit" class="btn btn-primary btn-sm" value="--hwdiff" name="difftype"> Inline </button> </form> </td> </tr> <tr> <td></td> <th scope="row">Authors</th> <td class="edit"> </td> <td> <span ><a title="Datatracker profile of Martin Thomson" href="/person/mt@lowentropy.net" >Martin Thomson</a> <a href="mailto:mt%40lowentropy.net" aria-label="Compose email to mt@lowentropy.net" title="Compose email to mt@lowentropy.net"> <i class="bi bi-envelope"></i></a></span>, <span ><a title="Datatracker profile of James Winterbottom" href="/person/a.james.winterbottom@gmail.com" >James Winterbottom</a> <a href="mailto:a.james.winterbottom%40gmail.com" aria-label="Compose email to a.james.winterbottom@gmail.com" title="Compose email to a.james.winterbottom@gmail.com"> <i class="bi bi-envelope"></i></a></span>, <span ><a title="Datatracker profile of Hannes Tschofenig" href="/person/Hannes.Tschofenig@gmx.net" >Hannes Tschofenig</a> <a href="mailto:Hannes.Tschofenig%40gmx.net" aria-label="Compose email to Hannes.Tschofenig@gmx.net" title="Compose email to Hannes.Tschofenig@gmx.net"> <i class="bi bi-envelope"></i></a></span> <br> <a class="btn btn-primary btn-sm mt-1" href="mailto:rfc5491@ietf.org?subject=rfc5491" title="Send email to the document authors">Email authors</a> </td> </tr> <tr> <td></td> <th scope="row"> RFC stream </th> <td class="edit"> </td> <td > <img alt="IETF Logo" class="d-lm-none w-25 mt-1" src="https://static.ietf.org/dt/12.28.2/ietf/images/ietf-logo-nor-white.svg" > <img alt="IETF Logo" class="d-dm-none w-25 mt-1" src="https://static.ietf.org/dt/12.28.2/ietf/images/ietf-logo-nor.svg" > </td> </tr> <tr> <td></td> <th scope="row"> Other formats </th> <td class="edit"> </td> <td> <div class="buttonlist"> <a class="btn btn-primary btn-sm" target="_blank" href="https://www.rfc-editor.org/rfc/rfc5491.txt"> <i class="bi bi-file-text"></i> txt </a> <a class="btn btn-primary btn-sm" target="_blank" href="https://www.rfc-editor.org/rfc/rfc5491.html"> <i class="bi bi-file-code"></i> html </a> <a class="btn btn-primary btn-sm" download="rfc5491.pdf" target="_blank" href="https://www.rfc-editor.org/rfc/pdfrfc/rfc5491.txt.pdf"> <i class="bi bi-file-pdf"></i> pdf </a> <a class="btn btn-primary btn-sm" target="_blank" href="https://www.rfc-editor.org/rfc/inline-errata/rfc5491.html"> <i class="bi bi-file-diff"></i> w/errata </a> <a class="btn btn-primary btn-sm" target="_blank" href="/doc/rfc5491/bibtex/"> <i class="bi bi-file-ruled"></i> bibtex </a> </div> </td> </tr> <tr> <td> </td> <th scope="row"> Additional resources </th> <td class="edit"> </td> <td> <a href="https://mailarchive.ietf.org/arch/browse/geopriv?q=rfc5491 OR %22draft-ietf-geopriv-pdif-lo-profile%22"> Mailing list discussion </a> </td> </tr> </tbody> <tr> <th scope="row"></th> <th scope="row"></th> <td class="edit"></td> <td> <a class="btn btn-sm btn-warning mb-3" target="_blank" href="https://github.com/ietf-tools/datatracker/issues/new/choose"> Report a bug <i class="bi bi-bug"></i> </a> </td> </tr> </table> </div> </div> </nav> <div class="row g-0"> <div class="col-md-9 d-flex justify-content-center lh-sm" data-bs-spy="scroll" data-bs-target="#toc-nav" data-bs-smooth-scroll="true" tabindex="0" id="content"> <div class="rfcmarkup"> <br class="noprint">  <div class="rfcmarkup"><pre>Network Working Group J. Winterbottom Request for Comments: 5491 M. Thomson Updates: <a href="/doc/html/rfc4119">4119</a> Andrew Corporation Category: Standards Track H. Tschofenig Nokia Siemens Networks March 2009 <span class="h1">GEOPRIV Presence Information Data Format Location Object (PIDF-LO)</span> <span class="h1">Usage Clarification, Considerations, and Recommendations</span> Status of This Memo This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited. Copyright Notice Copyright (c) 2009 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to <a href="/doc/html/bcp78">BCP 78</a> and the IETF Trust's Legal Provisions Relating to IETF Documents in effect on the date of publication of this document (<a href="http://trustee.ietf.org/license-info">http://trustee.ietf.org/license-info</a>). Please review these documents carefully, as they describe your rights and restrictions with respect to this document. <span class="grey">Winterbottom, et al. Standards Track [Page 1]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-2" ></span> <span class="grey"><a href="/doc/html/rfc5491">RFC 5491</a> GEOPRIV PIDF-LO Usage March 2009</span> Abstract The Presence Information Data Format Location Object (PIDF-LO) specification provides a flexible and versatile means to represent location information. There are, however, circumstances that arise when information needs to be constrained in how it is represented. In these circumstances, the range of options that need to be implemented are reduced. There is growing interest in being able to use location information contained in a PIDF-LO for routing applications. To allow successful interoperability between applications, location information needs to be normative and more tightly constrained than is currently specified in <a href="/doc/html/rfc4119">RFC 4119</a> (PIDF- LO). This document makes recommendations on how to constrain, represent, and interpret locations in a PIDF-LO. It further recommends a subset of Geography Markup Language (GML) 3.1.1 that is mandatory to implement by applications involved in location-based routing. Table of Contents <a href="#section-1">1</a>. Introduction ....................................................<a href="#page-3">3</a> <a href="#section-2">2</a>. Terminology .....................................................<a href="#page-3">3</a> <a href="#section-3">3</a>. Using Location Information ......................................<a href="#page-4">4</a> <a href="#section-3.1">3.1</a>. Single Civic Location Information ..........................<a href="#page-7">7</a> <a href="#section-3.2">3.2</a>. Civic and Geospatial Location Information ..................<a href="#page-7">7</a> <a href="#section-3.3">3.3</a>. Manual/Automatic Configuration of Location Information .....<a href="#page-8">8</a> <a href="#section-3.4">3.4</a>. Multiple Location Objects in a Single PIDF-LO ..............<a href="#page-9">9</a> <a href="#section-4">4</a>. Geodetic Coordinate Representation .............................<a href="#page-10">10</a> <a href="#section-5">5</a>. Geodetic Shape Representation ..................................<a href="#page-10">10</a> <a href="#section-5.1">5.1</a>. Polygon Restrictions ......................................<a href="#page-12">12</a> <a href="#section-5.2">5.2</a>. Shape Examples ............................................<a href="#page-13">13</a> <a href="#section-5.2.1">5.2.1</a>. Point ..............................................<a href="#page-13">13</a> <a href="#section-5.2.2">5.2.2</a>. Polygon ............................................<a href="#page-14">14</a> <a href="#section-5.2.3">5.2.3</a>. Circle .............................................<a href="#page-17">17</a> <a href="#section-5.2.4">5.2.4</a>. Ellipse ............................................<a href="#page-17">17</a> <a href="#section-5.2.5">5.2.5</a>. Arc Band ...........................................<a href="#page-19">19</a> <a href="#section-5.2.6">5.2.6</a>. Sphere .............................................<a href="#page-21">21</a> <a href="#section-5.2.7">5.2.7</a>. Ellipsoid ..........................................<a href="#page-22">22</a> <a href="#section-5.2.8">5.2.8</a>. Prism ..............................................<a href="#page-24">24</a> <a href="#section-6">6</a>. Security Considerations ........................................<a href="#page-26">26</a> <a href="#section-7">7</a>. Acknowledgments ................................................<a href="#page-26">26</a> <a href="#section-8">8</a>. References .....................................................<a href="#page-26">26</a> <a href="#section-8.1">8.1</a>. Normative References ......................................<a href="#page-26">26</a> <a href="#section-8.2">8.2</a>. Informative References ....................................<a href="#page-27">27</a> <span class="grey">Winterbottom, et al. Standards Track [Page 2]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-3" ></span> <span class="grey"><a href="/doc/html/rfc5491">RFC 5491</a> GEOPRIV PIDF-LO Usage March 2009</span> <span class="h2"><a class="selflink" id="section-1" href="#section-1">1</a>. Introduction</span> The Presence Information Data Format Location Object (PIDF-LO) [<a href="/doc/html/rfc4119" title=""A Presence-based GEOPRIV Location Object Format"">RFC4119</a>] is the recommended way of encoding location information and associated privacy policies. Location information in a PIDF-LO may be described in a geospatial manner based on a subset of Geography Markup Language (GML) 3.1.1 [<a href="#ref-OGC-GML3.1.1">OGC-GML3.1.1</a>] or as civic location information [<a href="/doc/html/rfc5139" title=""Revised Civic Location Format for Presence Information Data Format Location Object (PIDF-LO)"">RFC5139</a>]. A GML profile for expressing geodetic shapes in a PIDF-LO is described in [<a href="#ref-GeoShape" title=""GML 3.1.1 PIDF-LO Shape Application Schema for use by the Internet Engineering Task Force (IETF)"">GeoShape</a>]. Uses for the PIDF-LO are envisioned in the context of numerous location-based applications. This document makes recommendations for formats and conventions to make interoperability less problematic. The PIDF-LO provides a general presence format for representing location information, and permits specification of location information relating to a whole range of aspects of a Target. The general presence data model is described in [<a href="/doc/html/rfc4479" title=""A Data Model for Presence"">RFC4479</a>] and caters to a presence document to describe different aspects of the reachability of a presentity. Continuing this approach, a presence document may contain several GEOPRIV objects that specify different locations and aspects of reachability relating to a presentity. This degree of flexibility is important, and recommendations in this document make no attempt to forbid the usage of a PIDF-LO in this manner. This document provides a specific set of guidelines for building presence documents when it is important to unambiguously convey exactly one location. <span class="h2"><a class="selflink" id="section-2" href="#section-2">2</a>. Terminology</span> 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 [<a href="/doc/html/rfc2119" title=""Key words for use in RFCs to Indicate Requirement Levels"">RFC2119</a>]. The definition for "Target" is taken from [<a href="/doc/html/rfc3693" title=""Geopriv Requirements"">RFC3693</a>]. In this document a "discrete location" is defined as a place, point, area, or volume in which a Target can be found. The term "compound location" is used to describe location information represented by a composite of both civic and geodetic information. An example of compound location might be a geodetic polygon describing the perimeter of a building and a civic element representing the floor in the building. The term "method" in this document refers to the mechanism used to determine the location of a Target. This may be something employed by a location information server (LIS), or by the Target itself. It <span class="grey">Winterbottom, et al. Standards Track [Page 3]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-4" ></span> <span class="grey"><a href="/doc/html/rfc5491">RFC 5491</a> GEOPRIV PIDF-LO Usage March 2009</span> specifically does not refer to the location configuration protocol (LCP) used to deliver location information either to the Target or the Recipient. The term "source" is used to refer to the LIS, node, or device from which a Recipient (Target or Third-Party) obtains location information. <span class="h2"><a class="selflink" id="section-3" href="#section-3">3</a>. Using Location Information</span> The PIDF format provides for an unbounded number of <tuple>, <device>, and <person> elements. Each of these elements contains a single <status> element that may contain more than one <geopriv> element as a child. Each <geopriv> element must contain at least the following two child elements: <location-info> element and <usage- rules> element. One or more elements containing location information are contained inside a <location-info> element. Hence, a single PIDF document may contain an arbitrary number of location objects, some or all of which may be contradictory or complementary. Graphically, the structure of a PIDF-LO document can be depicted as shown in Figure 1. <span class="grey">Winterbottom, et al. Standards Track [Page 4]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-5" ></span> <span class="grey"><a href="/doc/html/rfc5491">RFC 5491</a> GEOPRIV PIDF-LO Usage March 2009</span> <presence> <tuple> -- #1 <status> <geopriv> -- #1 <location-info> location element #1 location element #2 ... location element #n <usage-rules> </geopriv> <geopriv> -- #2 <geopriv> -- #3 ... <geopriv> -- #m </status> </tuple> <device> <geopriv> -- #1 <location-info> location element(s) <usage-rules> </geopriv> <geopriv> -- #2 ... <geopriv> -- #m </device> <person> <geopriv> -- #1 <location-info> location element(s) <usage-rules> </geopriv> <geopriv> -- #2 ... <geopriv> -- #m </person> <tuple> -- #2 <device> -- #2 <person> -- #2 ... <tuple> -- #o </presence> Figure 1: Structure of a PIDF-LO Document <span class="grey">Winterbottom, et al. Standards Track [Page 5]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-6" ></span> <span class="grey"><a href="/doc/html/rfc5491">RFC 5491</a> GEOPRIV PIDF-LO Usage March 2009</span> All of these potential sources and storage places for location lead to confusion for the generators, conveyors, and consumers of location information. Practical experience within the United States National Emergency Number Association (NENA) in trying to solve these ambiguities led to a set of conventions being adopted. These rules do not have any particular order, but should be followed by creators and consumers of location information contained in a PIDF-LO to ensure that a consistent interpretation of the data can be achieved. Rule #1: A <geopriv> element MUST describe a discrete location. Rule #2: Where a discrete location can be uniquely described in more than one way, each location description SHOULD reside in a separate <tuple>, <device>, or <person> element; only one geopriv element per tuple. Rule #3: Providing more than one <geopriv> element in a single presence document (PIDF) MUST only be done if the locations refer to the same place or are put into different element types. For example, one location in a <tuple>, a second location in a <device> element, and a third location in a <person> element. This may occur if a Target's location is determined using a series of different techniques or if the Target wishes to represent her location as well as the location of her PC. In general, avoid putting more than one location into a document unless it makes sense to do so. Rule #4: Providing more than one location chunk in a single <location-info> element SHOULD be avoided where possible. Rule #5 and Rule #6 provide further refinement. Rule #5: When providing more than one location chunk in a single <location-info> element, the locations MUST be provided by a common source at the same time and by the same location determination method. Rule #6: Providing more than one location chunk in a single <location-info> element SHOULD only be used for representing compound location referring to the same place. For example, a geodetic location describing a point, and a civic location indicating the floor in a building. <span class="grey">Winterbottom, et al. Standards Track [Page 6]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-7" ></span> <span class="grey"><a href="/doc/html/rfc5491">RFC 5491</a> GEOPRIV PIDF-LO Usage March 2009</span> Rule #7: Where the compound location is provided in a single <location-info> element, the coarse location information MUST be provided first. For example, a geodetic location describing an area and a civic location indicating the floor should be represented with the area first followed by the civic location. Rule #8: Where a PIDF document contains more than one <geopriv> element, the priority of interpretation is given to the first <device> element in the document containing a location. If no <device> element containing a location is present in the document, then priority is given to the first <tuple> element containing a location. Locations contained in <person> tuples SHOULD only be used as a last resort. Rule #9: Where multiple PIDF documents can be sent or received together, say in a multi-part MIME body, and current location information is required by the recipient, then document selection SHOULD be based on document order, with the first document considered first. The following examples illustrate the application of these rules. <span class="h3"><a class="selflink" id="section-3.1" href="#section-3.1">3.1</a>. Single Civic Location Information</span> Jane is at a coffee shop on the ground floor of a large shopping mall. Jane turns on her laptop and connects to the coffee shop's WiFi hotspot; Jane obtains a complete civic address for her current location, for example, using the DHCP civic mechanism defined in [<a href="/doc/html/rfc4776" title=""Dynamic Host Configuration Protocol (DHCPv4 and DHCPv6) Option for Civic Addresses Configuration Information"">RFC4776</a>]. A Location Object is constructed consisting of a single PIDF document, with a single <tuple> or <device> element, a single <status> element, a single <geopriv> element, and a single location chunk residing in the <location-info> element. This document is unambiguous, and should be interpreted consistently by receiving nodes if sent over the network. <span class="h3"><a class="selflink" id="section-3.2" href="#section-3.2">3.2</a>. Civic and Geospatial Location Information</span> Mike is visiting his Seattle office and connects his laptop into the Ethernet port in a spare cube. In this case, location information is geodetic location, with the altitude represented as a building floor number. Mike's main location is the point specified by the geodetic coordinates. Further, Mike is on the second floor of the building located at these coordinates. Applying rules #6 and #7, the resulting compound location information is shown in Figure 2. <span class="grey">Winterbottom, et al. Standards Track [Page 7]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-8" ></span> <span class="grey"><a href="/doc/html/rfc5491">RFC 5491</a> GEOPRIV PIDF-LO Usage March 2009</span> <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:gml="http://www.opengis.net/gml" xmlns:cl="urn:ietf:params:xml:ns:pidf:geopriv10:civicAddr" entity="pres:mike@seattle.example.com"> <dm:device id="mikepc"> <gp:geopriv> <gp:location-info> <gml:Point srsName="urn:ogc:def:crs:EPSG::4326"> <gml:pos>-43.5723 153.21760</gml:pos> </gml:Point> <cl:civicAddress> <cl:FLR>2</cl:FLR> </cl:civicAddress> </gp:location-info> <gp:usage-rules/> <gp:method>Wiremap</gp:method> </gp:geopriv> <dm:deviceID>mac:8asd7d7d70cf</dm:deviceID> <dm:timestamp>2007-06-22T20:57:29Z</dm:timestamp> </dm:device> </presence> Figure 2: PIDF-LO Containing a Compound Location <span class="h3"><a class="selflink" id="section-3.3" href="#section-3.3">3.3</a>. Manual/Automatic Configuration of Location Information</span> Loraine has a predefined civic location stored in her laptop, since she normally lives in Sydney, the address is for her Sydney-based apartment. Loraine decides to visit sunny San Francisco, and when she gets there, she plugs in her laptop and makes a call. Loraine's laptop receives a new location from the visited network in San Francisco. As this system cannot be sure that the preexisting and new location both describe the same place, Loraine's computer generates a new PIDF-LO and will use this to represent Loraine's location. If Loraine's computer were to add the new location to her existing PIDF location document (breaking rule #3), then the correct information may still be interpreted by the Location Recipient providing Loraine's system applies rule #9. In this case, the resulting order of location information in the PIDF document should be San Francisco first, followed by Sydney. Since the information is provided by different sources, rule #8 should also be applied and the information placed in different tuples with the tuple containing the San Francisco location first. <span class="grey">Winterbottom, et al. Standards Track [Page 8]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-9" ></span> <span class="grey"><a href="/doc/html/rfc5491">RFC 5491</a> GEOPRIV PIDF-LO Usage March 2009</span> <span class="h3"><a class="selflink" id="section-3.4" href="#section-3.4">3.4</a>. Multiple Location Objects in a Single PIDF-LO</span> Vanessa has her PC with her at the park, but due to a misconfiguration, her PC reports her location as being in the office. The resulting PIDF-LO will have a <device> element showing the location of Vanessa's PC as the park, and a <person> element saying that Vanessa is in her office. <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: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:RDBR>Campbell Street</ca:RDBR> <ca:LMK> Gilligan's Island </ca:LMK> <ca:LOC>Corner</ca:LOC> <ca:NAM> Video Rental Store </ca:NAM> <ca:PC>2500</ca:PC> <ca:ROOM> Westerns and Classics </ca:ROOM> <ca:PLC>store</ca:PLC> <ca:POBOX>Private Box 15</ca:POBOX> </ca:civicAddress> </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> <dm:person id="ness"> <gp:geopriv> <gp:location-info> <gs:Circle srsName="urn:ogc:def:crs:EPSG::4326"> <gml:pos>-34.410649 150.87651</gml:pos> <gs:radius uom="urn:ogc:def:uom:EPSG::9001"> <span class="grey">Winterbottom, et al. Standards Track [Page 9]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-10" ></span> <span class="grey"><a href="/doc/html/rfc5491">RFC 5491</a> GEOPRIV PIDF-LO Usage March 2009</span> 30 </gs:radius> </gs:Circle> </gp:location-info> <gp:usage-rules/> <gp:method>Manual</gp:method> </gp:geopriv> <dm:timestamp>2007-06-24T12:28:04Z</dm:timestamp> </dm:person> </presence> Figure 3: PIDF-LO Containing Multiple Location Objects <span class="h2"><a class="selflink" id="section-4" href="#section-4">4</a>. Geodetic Coordinate Representation</span> The geodetic examples provided in <a href="/doc/html/rfc4119">RFC 4119</a> [<a href="/doc/html/rfc4119" title=""A Presence-based GEOPRIV Location Object Format"">RFC4119</a>] are illustrated using the <gml:location> element, which uses the <gml:coordinates> element inside the <gml:Point> element, and this representation has several drawbacks. Firstly, it has been deprecated in later versions of GML (3.1 and beyond) making it inadvisable to use for new applications. Secondly, the format of the coordinates type is opaque and so can be difficult to parse and interpret to ensure consistent results, as the same geodetic location can be expressed in a variety of ways. The PIDF-LO Geodetic Shapes specification [<a href="#ref-GeoShape" title=""GML 3.1.1 PIDF-LO Shape Application Schema for use by the Internet Engineering Task Force (IETF)"">GeoShape</a>] provides a specific GML profile for expressing commonly used shapes using simple GML representations. The shapes defined in [<a href="#ref-GeoShape" title=""GML 3.1.1 PIDF-LO Shape Application Schema for use by the Internet Engineering Task Force (IETF)"">GeoShape</a>] are the recommended shapes to ensure interoperability. <span class="h2"><a class="selflink" id="section-5" href="#section-5">5</a>. Geodetic Shape Representation</span> The cellular mobile world today makes extensive use of geodetic-based location information for emergency and other location-based applications. Generally, these locations are expressed as a point (either in two or three dimensions) and an area or volume of uncertainty around the point. In theory, the area or volume represents a coverage in which the user has a relatively high probability of being found, and the point is a convenient means of defining the centroid for the area or volume. In practice, most systems use the point as an absolute value and ignore the uncertainty. It is difficult to determine if systems have been implemented in this manner for simplicity, and even more difficult to predict if uncertainty will play a more important role in the future. An important decision is whether an uncertainty area should be specified. <span class="grey">Winterbottom, et al. Standards Track [Page 10]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-11" ></span> <span class="grey"><a href="/doc/html/rfc5491">RFC 5491</a> GEOPRIV PIDF-LO Usage March 2009</span> The PIDF-LO Geodetic Shapes specification [<a href="#ref-GeoShape" title=""GML 3.1.1 PIDF-LO Shape Application Schema for use by the Internet Engineering Task Force (IETF)"">GeoShape</a>] defines eight shape types, most of which are easily translated into shape definitions used in other applications and protocols, such as the Open Mobile Alliance (OMA) Mobile Location Protocol (MLP). For completeness, the shapes defined in [<a href="#ref-GeoShape" title=""GML 3.1.1 PIDF-LO Shape Application Schema for use by the Internet Engineering Task Force (IETF)"">GeoShape</a>] are listed below: o Point (2d and 3d) o Polygon (2d) o Circle (2d) o Ellipse (2d) o Arc band (2d) o Sphere (3d) o Ellipsoid (3d) o Prism (3d) The above-listed shapes MUST be implemented. The GeoShape specification [<a href="#ref-GeoShape" title=""GML 3.1.1 PIDF-LO Shape Application Schema for use by the Internet Engineering Task Force (IETF)"">GeoShape</a>] also describes a standard set of coordinate reference systems (CRS), unit of measure (UoM) and conventions relating to lines and distances. The use of the world geodetic system 1984 (WGS84) [<a href="#ref-WGS84" title=""Department of Defense (DoD) World Geodetic System 1984 (WGS 84), Third Edition"">WGS84</a>] coordinate reference system and the usage of European petroleum survey group (EPSG) code 4326 (as identified by the URN urn:ogc:def:crs:EPSG::4326, [<a href="#ref-CRS-URN" title=""GML 3.1.1 Common CRSs Profile"">CRS-URN</a>]) for two- dimensional (2d) shape representations and EPSG 4979 (as identified by the URN urn:ogc:def:crs:EPSG::4979) for three-dimensional (3d) volume representations is mandated. Distance and heights are expressed in meters using EPSG 9001 (as identified by the URN urn:ogc:def:uom:EPSG::9001). Angular measures MUST use either degrees or radians. Measures in degrees MUST be identified by the URN urn:ogc:def:uom:EPSG::9102, measures in radians MUST be identified by the URN urn:ogc:def:uom:EPSG::9101. Angles representing bearings are measured in a clockwise direction from Northing, as defined by the WGS84 CRS, not magnetic north. Implementations MUST specify the CRS using the srsName attribute on the outermost geometry element. The CRS MUST NOT be respecified or changed for any sub-elements. The srsDimension attribute SHOULD be omitted, since the number of dimensions in these CRSs is known. A CRS MUST be specified using the above URN notation only; implementations do not need to support user-defined CRSs. <span class="grey">Winterbottom, et al. Standards Track [Page 11]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-12" ></span> <span class="grey"><a href="/doc/html/rfc5491">RFC 5491</a> GEOPRIV PIDF-LO Usage March 2009</span> Numerical values for coordinates and measures are expressed using the lexical representation for "double" defined in [<a href="#ref-W3C.REC-xmlschema-2-20041028">W3C.REC-xmlschema-2-20041028</a>]. Leading zeros and trailing zeros past the decimal point are not significant; for instance "03.07500" is equivalent to "3.075". It is RECOMMENDED that uncertainty is expressed at a confidence of 95% or higher. Specifying a convention for confidence enables better use of uncertainty values. <span class="h3"><a class="selflink" id="section-5.1" href="#section-5.1">5.1</a>. Polygon Restrictions</span> The polygon shape type defined in [<a href="#ref-GeoShape" title=""GML 3.1.1 PIDF-LO Shape Application Schema for use by the Internet Engineering Task Force (IETF)"">GeoShape</a>] intentionally does not place any constraints on the number of vertices that may be included to define the bounds of a polygon. This allows arbitrarily complex shapes to be defined and conveyed in a PIDF-LO. However, where location information is to be used in real-time processing applications, such as location-dependent routing, having arbitrarily complex shapes consisting of tens or even hundreds of points could result in significant performance impacts. To mitigate this risk, Polygon shapes SHOULD be restricted to a maximum of 15 points (16 including the repeated point) when the location information is intended for use in real-time applications. This limit of 15 points is chosen to allow moderately complex shape definitions while at the same time enabling interoperation with other location transporting protocols such as those defined in the 3rd Generation Partnership Project (3GPP) (see [<a href="#ref-3GPP.23.032">3GPP.23.032</a>]) and OMA where the 15-point limit is already imposed. The edges of a polygon are defined by the shortest path between two points in space (not a geodesic curve). Two-dimensional points MAY be interpreted as having a zero value for their altitude component. To avoid significant errors arising from potential geodesic interpolation, the length between adjacent vertices SHOULD be restricted to a maximum of 130 km. More information relating to this restriction is provided in [<a href="#ref-GeoShape" title=""GML 3.1.1 PIDF-LO Shape Application Schema for use by the Internet Engineering Task Force (IETF)"">GeoShape</a>]. A connecting line SHALL NOT cross another connecting line of the same Polygon. Polygons MUST be defined with the upward normal pointing up. This is accomplished by defining the vertices in a counter-clockwise direction. Points specified in a polygon using three-dimensional coordinates MUST all have the same altitude. <span class="grey">Winterbottom, et al. Standards Track [Page 12]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-13" ></span> <span class="grey"><a href="/doc/html/rfc5491">RFC 5491</a> GEOPRIV PIDF-LO Usage March 2009</span> <span class="h3"><a class="selflink" id="section-5.2" href="#section-5.2">5.2</a>. Shape Examples</span> This section provides some examples of where some of the more complex shapes are used, how they are determined, and how they are represented in a PIDF-LO. Complete details on all of the GeoShape types are provided in [<a href="#ref-GeoShape" title=""GML 3.1.1 PIDF-LO Shape Application Schema for use by the Internet Engineering Task Force (IETF)"">GeoShape</a>]. <span class="h4"><a class="selflink" id="section-5.2.1" href="#section-5.2.1">5.2.1</a>. Point</span> The point shape type is the simplest form of geodetic location information (LI), which is natively supported by GML. The gml:Point element is used when there is no known uncertainty. A point also forms part of a number of other geometries. A point may be specified using either WGS 84 (latitude, longitude) or WGS 84 (latitude, longitude, altitude). Figure 4 shows a 2d point: <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:cl="urn:ietf:params:xml:ns:pidf:geopriv10:civicAddr" xmlns:gml="http://www.opengis.net/gml" entity="pres:point2d@example.com"> <dm:device id="point2d"> <gp:geopriv> <gp:location-info> <gml:Point srsName="urn:ogc:def:crs:EPSG::4326"> <gml:pos>-34.407 150.883</gml:pos> </gml:Point> </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> </presence> Figure 4: PIDF-LO Containing a Two-Dimensional Point <span class="grey">Winterbottom, et al. Standards Track [Page 13]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-14" ></span> <span class="grey"><a href="/doc/html/rfc5491">RFC 5491</a> GEOPRIV PIDF-LO Usage March 2009</span> Figure 5 shows a 3d point: <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:gml="http://www.opengis.net/gml" entity="pres:point3d@example.com"> <dm:device id="point3d"> <gp:geopriv> <gp:location-info> <gml:Point srsName="urn:ogc:def:crs:EPSG::4979" xmlns:gml="http://www.opengis.net/gml"> <gml:pos>-34.407 150.883 24.8</gml:pos> </gml:Point> </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> </presence> Figure 5: PIDF-LO Containing a Three-Dimensional Point <span class="h4"><a class="selflink" id="section-5.2.2" href="#section-5.2.2">5.2.2</a>. Polygon</span> The polygon shape type may be used to represent a building outline or coverage area. The first and last points of the polygon have to be the same. For example, looking at the hexagon in Figure 6 with vertices, A, B, C, D, E, and F. The resulting polygon will be defined with 7 points, with the first and last points both having the coordinates of point A. F--------------E / \ / \ / \ A D \ / \ / \ / B--------------C Figure 6: Example of a Polygon <span class="grey">Winterbottom, et al. Standards Track [Page 14]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-15" ></span> <span class="grey"><a href="/doc/html/rfc5491">RFC 5491</a> GEOPRIV PIDF-LO Usage March 2009</span> <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:hexagon@example.com"> <tuple id="polygon-pos"> <status> <gp:geopriv> <gp:location-info> <gml:Polygon srsName="urn:ogc:def:crs:EPSG::4326"> <gml:exterior> <gml:LinearRing> <gml:pos>43.311 -73.422</gml:pos>  <gml:pos>43.111 -73.322</gml:pos>  <gml:pos>43.111 -73.222</gml:pos>  <gml:pos>43.311 -73.122</gml:pos>  <gml:pos>43.411 -73.222</gml:pos>  <gml:pos>43.411 -73.322</gml:pos>  <gml:pos>43.311 -73.422</gml:pos>  </gml:LinearRing> </gml:exterior> </gml:Polygon> </gp:location-info> <gp:usage-rules/> <gp:method>Wiremap</gp:method> </gp:geopriv> </status> <timestamp>2007-06-22T20:57:29Z</timestamp> </tuple> </presence> Figure 7: PIDF-LO Containing a Polygon In addition to the form shown in Figure 7, GML supports a posList that provides a more compact representation for the coordinates of the Polygon vertices than the discrete pos elements. The more compact form is shown in Figure 8. Both forms are permitted. <span class="grey">Winterbottom, et al. Standards Track [Page 15]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-16" ></span> <span class="grey"><a href="/doc/html/rfc5491">RFC 5491</a> GEOPRIV PIDF-LO Usage March 2009</span> <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:hexagon@example.com"> <tuple id="polygon-poslist"> <status> <gp:geopriv> <gp:location-info> <gml:Polygon srsName="urn:ogc:def:crs:EPSG::4326"> <gml:exterior> <gml:LinearRing> <gml:posList> 43.311 -73.422 43.111 -73.322 43.111 -73.222 43.311 -73.122 43.411 -73.222 43.411 -73.322 43.311 -73.422 </gml:posList> </gml:LinearRing> </gml:exterior> </gml:Polygon> </gp:location-info> <gp:usage-rules/> <gp:method>Wiremap</gp:method> </gp:geopriv> </status> <timestamp>2007-06-22T20:57:29Z</timestamp> </tuple> </presence> Figure 8: Compact Form of a Polygon Expressed in a PIDF-LO <span class="grey">Winterbottom, et al. Standards Track [Page 16]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-17" ></span> <span class="grey"><a href="/doc/html/rfc5491">RFC 5491</a> GEOPRIV PIDF-LO Usage March 2009</span> <span class="h4"><a class="selflink" id="section-5.2.3" href="#section-5.2.3">5.2.3</a>. Circle</span> The circular area is used for coordinates in two-dimensional CRSs to describe uncertainty about a point. The definition is based on the one-dimensional geometry in GML, gml:CircleByCenterPoint. The center point of a circular area is specified by using a two-dimensional CRS; in three dimensions, the orientation of the circle cannot be specified correctly using this representation. A point with uncertainty that is specified in three dimensions should use the sphere shape type. <presence xmlns="urn:ietf:params:xml:ns:pidf" xmlns:gp="urn:ietf:params:xml:ns:pidf:geopriv10" xmlns:gml="http://www.opengis.net/gml" xmlns:gs="http://www.opengis.net/pidflo/1.0" entity="pres:circle@example.com"> <tuple id="circle"> <status> <gp:geopriv> <gp:location-info> <gs:Circle srsName="urn:ogc:def:crs:EPSG::4326"> <gml:pos>42.5463 -73.2512</gml:pos> <gs:radius uom="urn:ogc:def:uom:EPSG::9001"> 850.24 </gs:radius> </gs:Circle> </gp:location-info> <gp:usage-rules/> <gp:method>OTDOA</gp:method> </gp:geopriv> </status> </tuple> </presence> Figure 9: PIDF-LO Containing a Circle <span class="h4"><a class="selflink" id="section-5.2.4" href="#section-5.2.4">5.2.4</a>. Ellipse</span> An elliptical area describes an ellipse in two-dimensional space. The ellipse is described by a center point, the length of its semi- major and semi-minor axes, and the orientation of the semi-major axis. Like the circular area (Circle), the ellipse MUST be specified using the two-dimensional CRS. <span class="grey">Winterbottom, et al. Standards Track [Page 17]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-18" ></span> <span class="grey"><a href="/doc/html/rfc5491">RFC 5491</a> GEOPRIV PIDF-LO Usage March 2009</span> <presence xmlns="urn:ietf:params:xml:ns:pidf" xmlns:gp="urn:ietf:params:xml:ns:pidf:geopriv10" xmlns:gml="http://www.opengis.net/gml" xmlns:gs="http://www.opengis.net/pidflo/1.0" entity="pres:Ellipse@somecell.example.com"> <tuple id="ellipse"> <status> <gp:geopriv> <gp:location-info> <gs:Ellipse srsName="urn:ogc:def:crs:EPSG::4326"> <gml:pos>42.5463 -73.2512</gml:pos> <gs:semiMajorAxis uom="urn:ogc:def:uom:EPSG::9001"> 1275 </gs:semiMajorAxis> <gs:semiMinorAxis uom="urn:ogc:def:uom:EPSG::9001"> 670 </gs:semiMinorAxis> <gs:orientation uom="urn:ogc:def:uom:EPSG::9102"> 43.2 </gs:orientation> </gs:Ellipse> </gp:location-info> <gp:usage-rules/> <gp:method>Device-Assisted_A-GPS</gp:method> </gp:geopriv> </status> <timestamp>2007-06-22T20:57:29Z</timestamp> </tuple> </presence> Figure 10: PIDF-LO Containing an Ellipse The gml:pos element indicates the position of the center, or origin, of the ellipse. The gs:semiMajorAxis and gs:semiMinorAxis elements are the length of the semi-major and semi-minor axes, respectively. The gs:orientation element is the angle by which the semi-major axis is rotated from the first axis of the CRS towards the second axis. For WGS 84, the orientation indicates rotation from Northing to Easting, which, if specified in degrees, is roughly equivalent to a compass bearing (if magnetic north were the same as the WGS north pole). Note: An ellipse with equal major and minor axis lengths is a circle. <span class="grey">Winterbottom, et al. Standards Track [Page 18]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-19" ></span> <span class="grey"><a href="/doc/html/rfc5491">RFC 5491</a> GEOPRIV PIDF-LO Usage March 2009</span> <span class="h4"><a class="selflink" id="section-5.2.5" href="#section-5.2.5">5.2.5</a>. Arc Band</span> The arc band shape type is commonly generated in wireless systems where timing advance or code offsets sequences are used to compensate for distances between handsets and the access point. The arc band is represented as two radii emanating from a central point, and two angles that represent the starting angle and the opening angle of the arc. In a cellular environment, the central point is nominally the location of the cell tower, the two radii are determined by the extent of the timing advance, and the two angles are generally provisioned information. For example, Paul is using a cellular wireless device and is 7 timing advance symbols away from the cell tower. For a GSM-based network, this would place Paul roughly between 3,594 meters and 4,148 meters from the cell tower, providing the inner and outer radius values. If the start angle is 20 degrees from north, and the opening angle is 120 degrees, an arc band representing Paul's location would look similar to Figure 11. N ^ ,.__ | a(s) / `-. | 20 / `-. |--. / `. | `/ \ | /__ \ | . `-. \ | . `. \ |. \ \ . ---c-- a(o) -- | | --> |. / 120 ' | E | . / ' | . / ; .,' / r(i)`. / (3594m) `. / `. ,' `. ,' r(o)`' (4148m) Figure 11: Example of an Arc Band The resulting PIDF-LO is shown in Figure 12. <span class="grey">Winterbottom, et al. Standards Track [Page 19]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-20" ></span> <span class="grey"><a href="/doc/html/rfc5491">RFC 5491</a> GEOPRIV PIDF-LO Usage March 2009</span> <presence xmlns="urn:ietf:params:xml:ns:pidf" xmlns:gp="urn:ietf:params:xml:ns:pidf:geopriv10" xmlns:gml="http://www.opengis.net/gml" xmlns:gs="http://www.opengis.net/pidflo/1.0" entity="pres:paul@somecell.example.com"> <tuple id="arcband"> <status> <gp:geopriv> <gp:location-info> <gs:ArcBand srsName="urn:ogc:def:crs:EPSG::4326"> <gml:pos>-43.5723 153.21760</gml:pos> <gs:innerRadius uom="urn:ogc:def:uom:EPSG::9001"> 3594 </gs:innerRadius> <gs:outerRadius uom="urn:ogc:def:uom:EPSG::9001"> 4148 </gs:outerRadius> <gs:startAngle uom="urn:ogc:def:uom:EPSG::9102"> 20 </gs:startAngle> <gs:openingAngle uom="urn:ogc:def:uom:EPSG::9102"> 20 </gs:openingAngle> </gs:ArcBand> </gp:location-info> <gp:usage-rules/> <gp:method>TA-NMR</gp:method> </gp:geopriv> </status> <timestamp>2007-06-22T20:57:29Z</timestamp> </tuple> </presence> Figure 12: PIDF-LO Containing an Arc Band An important note to make on the arc band is that the center point used in the definition of the shape is not included in resulting enclosed area, and that Target may be anywhere in the defined area of the arc band. <span class="grey">Winterbottom, et al. Standards Track [Page 20]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-21" ></span> <span class="grey"><a href="/doc/html/rfc5491">RFC 5491</a> GEOPRIV PIDF-LO Usage March 2009</span> <span class="h4"><a class="selflink" id="section-5.2.6" href="#section-5.2.6">5.2.6</a>. Sphere</span> The sphere is a volume that provides the same information as a circle in three dimensions. The sphere has to be specified using a three- dimensional CRS. Figure 13 shows the sphere shape type, which is identical to the circle example, except for the addition of an altitude in the provided coordinates. <presence xmlns="urn:ietf:params:xml:ns:pidf" xmlns:gp="urn:ietf:params:xml:ns:pidf:geopriv10" xmlns:gml="http://www.opengis.net/gml" xmlns:gs="http://www.opengis.net/pidflo/1.0" entity="pres:sphere@example.com"> <tuple id="sphere"> <status> <gp:geopriv> <gp:location-info> <gs:Sphere srsName="urn:ogc:def:crs:EPSG::4979"> <gml:pos>42.5463 -73.2512 26.3</gml:pos> <gs:radius uom="urn:ogc:def:uom:EPSG::9001"> 850.24 </gs:radius> </gs:Sphere> </gp:location-info> <gp:usage-rules/> <gp:method>Device-Based_A-GPS</gp:method> </gp:geopriv> </status> </tuple> </presence> Figure 13: PIDF-LO Containing a Sphere <span class="grey">Winterbottom, et al. Standards Track [Page 21]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-22" ></span> <span class="grey"><a href="/doc/html/rfc5491">RFC 5491</a> GEOPRIV PIDF-LO Usage March 2009</span> <span class="h4"><a class="selflink" id="section-5.2.7" href="#section-5.2.7">5.2.7</a>. Ellipsoid</span> The ellipsoid is the volume most commonly produced by GPS systems. It is used extensively in navigation systems and wireless location networks. The ellipsoid is constructed around a central point specified in three dimensions, and three axes perpendicular to one another are extended outwards from this point. These axes are defined as the semi-major (M) axis, the semi-minor (m) axis, and the vertical (v) axis, respectively. An angle is used to express the orientation of the ellipsoid. The orientation angle is measured in degrees from north, and represents the direction of the semi-major axis from the center point. \ _.-\""""^"""""-._ .' \ | `. / v m \ | \ | | | -c ----M---->| | | \ / `._ _.' `-...........-' Figure 14: Example of an Ellipsoid <span class="grey">Winterbottom, et al. Standards Track [Page 22]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-23" ></span> <span class="grey"><a href="/doc/html/rfc5491">RFC 5491</a> GEOPRIV PIDF-LO Usage March 2009</span> A PIDF-LO containing an ellipsoid appears as shown in Figure 15. <presence xmlns="urn:ietf:params:xml:ns:pidf" xmlns:gp="urn:ietf:params:xml:ns:pidf:geopriv10" xmlns:gml="http://www.opengis.net/gml" xmlns:gs="http://www.opengis.net/pidflo/1.0" entity="pres:somone@gpsreceiver.example.com"> <tuple id="ellipsoid"> <status> <gp:geopriv> <gp:location-info> <gs:Ellipsoid srsName="urn:ogc:def:crs:EPSG::4979"> <gml:pos>42.5463 -73.2512 26.3</gml:pos> <gs:semiMajorAxis uom="urn:ogc:def:uom:EPSG::9001"> 7.7156 </gs:semiMajorAxis> <gs:semiMinorAxis uom="urn:ogc:def:uom:EPSG::9001"> 3.31 </gs:semiMinorAxis> <gs:verticalAxis uom="urn:ogc:def:uom:EPSG::9001"> 28.7 </gs:verticalAxis> <gs:orientation uom="urn:ogc:def:uom:EPSG::9102"> 90 </gs:orientation> </gs:Ellipsoid> </gp:location-info> <gp:usage-rules/> <gp:method>Hybrid_A-GPS</gp:method> </gp:geopriv> </status> <timestamp>2007-06-22T20:57:29Z</timestamp> </tuple> </presence> Figure 15: PIDF-LO Containing an Ellipsoid <span class="grey">Winterbottom, et al. Standards Track [Page 23]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-24" ></span> <span class="grey"><a href="/doc/html/rfc5491">RFC 5491</a> GEOPRIV PIDF-LO Usage March 2009</span> <span class="h4"><a class="selflink" id="section-5.2.8" href="#section-5.2.8">5.2.8</a>. Prism</span> A prism may be used to represent a section of a building or range of floors of building. The prism extrudes a polygon by providing a height element. It consists of a base made up of coplanar points defined in 3 dimensions all at the same altitude. The prism is then an extrusion from this base to the value specified in the height element. The height of the Prism MUST be a positive value. The first and last points of the polygon have to be the same. For example, looking at the cube in Figure 16: if the prism is extruded from the bottom up, then the polygon forming the base of the prism is defined with the points A, B, C, D, A. The height of the prism is the distance between point A and point E in meters. G-----F /| /| / | / | H--+--E | | C--|--B | / | / |/ |/ D-----A Figure 16: Example of a Prism <span class="grey">Winterbottom, et al. Standards Track [Page 24]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-25" ></span> <span class="grey"><a href="/doc/html/rfc5491">RFC 5491</a> GEOPRIV PIDF-LO Usage March 2009</span> The resulting PIDF-LO is shown in Figure 17. <presence xmlns="urn:ietf:params:xml:ns:pidf" xmlns:gp="urn:ietf:params:xml:ns:pidf:geopriv10" xmlns:gml="http://www.opengis.net/gml" xmlns:gs="http://www.opengis.net/pidflo/1.0" entity="pres:mike@someprism.example.com"> <tuple id="prism"> <status> <gp:geopriv> <gp:location-info> <gs:Prism srsName="urn:ogc:def:crs:EPSG::4979"> <gs:base> <gml:Polygon> <gml:exterior> <gml:LinearRing> <gml:posList> 42.556844 -73.248157 36.6  42.656844 -73.248157 36.6  42.656844 -73.348157 36.6  42.556844 -73.348157 36.6  42.556844 -73.248157 36.6  </gml:posList> </gml:LinearRing> </gml:exterior> </gml:Polygon> </gs:base> <gs:height uom="urn:ogc:def:uom:EPSG::9001"> 2.4 </gs:height> </gs:Prism> </gp:location-info> <gp:usage-rules/> <gp:method>Wiremap</gp:method> </gp:geopriv> </status> <timestamp>2007-06-22T20:57:29Z</timestamp> </tuple> </presence> Figure 17: PIDF-LO Containing a Prism <span class="grey">Winterbottom, et al. Standards Track [Page 25]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-26" ></span> <span class="grey"><a href="/doc/html/rfc5491">RFC 5491</a> GEOPRIV PIDF-LO Usage March 2009</span> <span class="h2"><a class="selflink" id="section-6" href="#section-6">6</a>. Security Considerations</span> The primary security considerations relate to how location information is conveyed and used, which are outside the scope of this document. This document is intended to serve only as a set of guidelines as to which elements MUST or SHOULD be implemented by systems wishing to perform location dependent routing. The ramification of such recommendations is that they extend to devices and clients that wish to make use of such services. <span class="h2"><a class="selflink" id="section-7" href="#section-7">7</a>. Acknowledgments</span> The authors would like to thank the GEOPRIV working group for their discussions in the context of PIDF-LO, in particular Carl Reed, Ron Lake, James Polk, Henning Schulzrinne, Jerome Grenier, Roger Marshall and Robert Sparks. Furthermore, we would like to thank Jon Peterson as the author of PIDF-LO and Nadine Abbott for her constructive comments in clarifying some aspects of the document. Thanks to Karen Navas for pointing out some omissions in the examples. <span class="h2"><a class="selflink" id="section-8" href="#section-8">8</a>. References</span> <span class="h3"><a class="selflink" id="section-8.1" href="#section-8.1">8.1</a>. Normative References</span> [<a id="ref-GeoShape">GeoShape</a>] Thomson, M. and C. Reed, "GML 3.1.1 PIDF-LO Shape Application Schema for use by the Internet Engineering Task Force (IETF)", Candidate OpenGIS Implementation Specification 06-142r1, Version: 1.0, April 2007. [<a id="ref-OGC-GML3.1.1">OGC-GML3.1.1</a>] Portele, C., Cox, S., Daisy, P., Lake, R., and A. Whiteside, "Geography Markup Language (GML) 3.1.1", OGC 03-105r1, July 2003. [<a id="ref-RFC2119">RFC2119</a>] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", <a href="/doc/html/bcp14">BCP 14</a>, <a href="/doc/html/rfc2119">RFC 2119</a>, March 1997. [<a id="ref-RFC4119">RFC4119</a>] Peterson, J., "A Presence-based GEOPRIV Location Object Format", <a href="/doc/html/rfc4119">RFC 4119</a>, December 2005. [<a id="ref-RFC4479">RFC4479</a>] Rosenberg, J., "A Data Model for Presence", <a href="/doc/html/rfc4479">RFC 4479</a>, July 2006. [<a id="ref-RFC5139">RFC5139</a>] Thomson, M. and J. Winterbottom, "Revised Civic Location Format for Presence Information Data Format Location Object (PIDF-LO)", <a href="/doc/html/rfc5139">RFC 5139</a>, February 2008. <span class="grey">Winterbottom, et al. Standards Track [Page 26]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-27" ></span> <span class="grey"><a href="/doc/html/rfc5491">RFC 5491</a> GEOPRIV PIDF-LO Usage March 2009</span> [<a id="ref-W3C.REC-xmlschema-2-20041028">W3C.REC-xmlschema-2-20041028</a>] Biron, P. and A. Malhotra, "XML Schema Part 2: Datatypes Second Edition", World Wide Web Consortium Recommendation REC-xmlschema-2-20041028, October 2004, <<a href="http://www.w3.org/TR/2004/REC-xmlschema-2-20041028">http://www.w3.org/TR/2004/REC-xmlschema-2-20041028</a>>. <span class="h3"><a class="selflink" id="section-8.2" href="#section-8.2">8.2</a>. Informative References</span> [<a id="ref-3GPP.23.032">3GPP.23.032</a>] 3rd Generation Partnership Project, "Universal Geographical Area Description (GAD)", 3GPP TS 23.032 V6.0.0, January 2005, <<a href="http://www.3gpp.org/ftp/Specs/html-info/23032.htm">http://www.3gpp.org/ftp/Specs/html-info/23032.htm</a>>. [<a id="ref-CRS-URN">CRS-URN</a>] Whiteside, A., "GML 3.1.1 Common CRSs Profile", OGC 03- 105r1, November 2005. [<a id="ref-RFC3693">RFC3693</a>] Cuellar, J., Morris, J., Mulligan, D., Peterson, J., and J. Polk, "Geopriv Requirements", <a href="/doc/html/rfc3693">RFC 3693</a>, February 2004. [<a id="ref-RFC4776">RFC4776</a>] Schulzrinne, H., "Dynamic Host Configuration Protocol (DHCPv4 and DHCPv6) Option for Civic Addresses Configuration Information", <a href="/doc/html/rfc4776">RFC 4776</a>, November 2006. [<a id="ref-WGS84">WGS84</a>] US National Imagery and Mapping Agency, "Department of Defense (DoD) World Geodetic System 1984 (WGS 84), Third Edition", NIMA TR8350.2, January 2000. <span class="grey">Winterbottom, et al. Standards Track [Page 27]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-28" ></span> <span class="grey"><a href="/doc/html/rfc5491">RFC 5491</a> GEOPRIV PIDF-LO Usage March 2009</span> Authors' Addresses James Winterbottom Andrew Corporation Wollongong NSW Australia EMail: james.winterbottom@andrew.com Martin Thomson Andrew Corporation Wollongong NSW Australia EMail: martin.thomson@andrew.com Hannes Tschofenig Nokia Siemens Networks Linnoitustie 6 Espoo 02600 Finland Phone: +358 (50) 4871445 EMail: Hannes.Tschofenig@gmx.net URI: <a href="http://www.tschofenig.priv.at">http://www.tschofenig.priv.at</a> Winterbottom, et al. Standards Track [Page 28] </pre></div> </div> </div> <div class="d-print-none col-md-3 bg-light-subtle collapse show" id="sidebar"> <div class="position-fixed border-start sidebar overflow-scroll overscroll-none no-scrollbar"> <div class="d-flex flex-column vh-100 pt-2 pt-lg-3 ps-3 pl-md-2 pl-lg-3"> <div> <a class="btn btn-primary btn-sm" href="/doc/rfc5491/">Datatracker</a> <p class="fw-bold pt-2"> RFC 5491 <br> <span class="text-success">RFC - Proposed Standard </span> </p> </div> <ul class="nav nav-tabs nav-fill small me-2" role="tablist"> <li class="nav-item" role="presentation" title="Document information"> <button class="nav-link px-2" id="docinfo-tab" data-bs-toggle="tab" data-bs-target="#docinfo-tab-pane" type="button" role="tab" aria-controls="docinfo-tab-pane" aria-selected="true"> <i class="bi bi-info-circle"></i><span class="d-none d-md-block d-xl-inline ms-xl-1">Info</span> </button> </li> <li class="nav-item" role="presentation" title="Table of contents"> <button class="nav-link px-2" id="toc-tab" data-bs-toggle="tab" data-bs-target="#toc-tab-pane" type="button" role="tab" aria-controls="toc-tab-pane" aria-selected="false"> <i class="bi bi-list-ol"></i><span class="d-none d-md-block d-xl-inline ms-xl-1">Contents</span> </button> </li> <li class="nav-item" role="presentation" title="Preferences"> <button class="nav-link px-2" id="pref-tab" data-bs-toggle="tab" data-bs-target="#pref-tab-pane" type="button" role="tab" aria-controls="pref-tab-pane" aria-selected="false"> <i class="bi bi-gear"></i><span class="d-none d-md-block d-xl-inline ms-xl-1">Prefs</span> </button> </li> </ul> <div class="overflow-auto tab-content pt-2 me-2"> <div class="tab-pane" id="docinfo-tab-pane" role="tabpanel" aria-labelledby="docinfo-tab" tabindex="0"> <table class="table table-sm table-borderless"> <tbody class="meta align-top "> <tr> <th scope="row">Document</th> <th scope="row">Document type</th> <td class="edit"></td> <td> <span class="text-success">RFC - Proposed Standard </span> <br>March 2009 <br> <a class="btn btn-primary btn-sm my-1" href="https://www.rfc-editor.org/errata_search.php?rfc=5491" title="Click to view errata." rel="nofollow"> View errata </a> <a class="btn btn-sm btn-warning" title="Click to report an error in the document." href="https://www.rfc-editor.org/errata.php#reportnew" target="_blank"> Report errata </a> <div>Updated by <a href="/doc/html/rfc7459" title="Representation of Uncertainty and Confidence in the Presence Information Data Format Location Object (PIDF-LO)">RFC 7459</a></div> <div>Updates <a href="/doc/html/rfc4119" title="A Presence-based GEOPRIV Location Object Format">RFC 4119</a></div> <div> Was <a href="/doc/draft-ietf-geopriv-pdif-lo-profile/14/">draft-ietf-geopriv-pdif-lo-profile</a> (<a href="/wg/geopriv/about/">geopriv WG</a>) </div> </td> </tr> <tr> <td></td> <th scope="row">Select version</th> <td class="edit"></td> <td> <ul class="revision-list pagination pagination-sm text-center flex-wrap my-0"> <li class="page-item"> <a class="page-link" href="/doc/html/draft-ietf-geopriv-pdif-lo-profile-14" rel="nofollow"> 14 </a> </li> <li class="page-item rfc active"> <a class="page-link" href="/doc/html/rfc5491"> RFC 5491 </a> </li> </ul> </td> </tr> <tr> <td></td> <th scope="row">Compare versions</th> <td class="edit"></td> <td> <form class="form-horizontal diff-form" action="https://author-tools.ietf.org/iddiff" method="get" target="_blank"> <select class="form-select form-select-sm mb-1 select2-field" data-max-entries="1" data-width="resolve" data-allow-clear="false" data-minimum-input-length="0" aria-label="From revision" name="url1"> <option value="rfc5491"> RFC 5491 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-14" selected> draft-ietf-geopriv-pdif-lo-profile-14 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-13"> draft-ietf-geopriv-pdif-lo-profile-13 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-12"> draft-ietf-geopriv-pdif-lo-profile-12 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-11"> draft-ietf-geopriv-pdif-lo-profile-11 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-10"> draft-ietf-geopriv-pdif-lo-profile-10 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-09"> draft-ietf-geopriv-pdif-lo-profile-09 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-08"> draft-ietf-geopriv-pdif-lo-profile-08 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-07"> draft-ietf-geopriv-pdif-lo-profile-07 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-06"> draft-ietf-geopriv-pdif-lo-profile-06 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-05"> draft-ietf-geopriv-pdif-lo-profile-05 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-04"> draft-ietf-geopriv-pdif-lo-profile-04 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-03"> draft-ietf-geopriv-pdif-lo-profile-03 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-02"> draft-ietf-geopriv-pdif-lo-profile-02 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-01"> draft-ietf-geopriv-pdif-lo-profile-01 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-00"> draft-ietf-geopriv-pdif-lo-profile-00 </option> </select> <select class="form-select form-select-sm mb-1 select2-field" data-max-entries="1" data-width="resolve" data-allow-clear="false" data-minimum-input-length="0" aria-label="To revision" name="url2"> <option value="rfc5491" selected> RFC 5491 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-14"> draft-ietf-geopriv-pdif-lo-profile-14 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-13"> draft-ietf-geopriv-pdif-lo-profile-13 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-12"> draft-ietf-geopriv-pdif-lo-profile-12 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-11"> draft-ietf-geopriv-pdif-lo-profile-11 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-10"> draft-ietf-geopriv-pdif-lo-profile-10 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-09"> draft-ietf-geopriv-pdif-lo-profile-09 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-08"> draft-ietf-geopriv-pdif-lo-profile-08 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-07"> draft-ietf-geopriv-pdif-lo-profile-07 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-06"> draft-ietf-geopriv-pdif-lo-profile-06 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-05"> draft-ietf-geopriv-pdif-lo-profile-05 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-04"> draft-ietf-geopriv-pdif-lo-profile-04 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-03"> draft-ietf-geopriv-pdif-lo-profile-03 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-02"> draft-ietf-geopriv-pdif-lo-profile-02 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-01"> draft-ietf-geopriv-pdif-lo-profile-01 </option> <option value="draft-ietf-geopriv-pdif-lo-profile-00"> draft-ietf-geopriv-pdif-lo-profile-00 </option> </select> <button type="submit" class="btn btn-primary btn-sm" value="--html" name="difftype"> Side-by-side </button> <button type="submit" class="btn btn-primary btn-sm" value="--hwdiff" name="difftype"> Inline </button> </form> </td> </tr> <tr> <td></td> <th scope="row">Authors</th> <td class="edit"> </td> <td> <span ><a title="Datatracker profile of Martin Thomson" href="/person/mt@lowentropy.net" >Martin Thomson</a> <a href="mailto:mt%40lowentropy.net" aria-label="Compose email to mt@lowentropy.net" title="Compose email to mt@lowentropy.net"> <i class="bi bi-envelope"></i></a></span>, <span ><a title="Datatracker profile of James Winterbottom" href="/person/a.james.winterbottom@gmail.com" >James Winterbottom</a> <a href="mailto:a.james.winterbottom%40gmail.com" aria-label="Compose email to a.james.winterbottom@gmail.com" title="Compose email to a.james.winterbottom@gmail.com"> <i class="bi bi-envelope"></i></a></span>, <span ><a title="Datatracker profile of Hannes Tschofenig" href="/person/Hannes.Tschofenig@gmx.net" >Hannes Tschofenig</a> <a href="mailto:Hannes.Tschofenig%40gmx.net" aria-label="Compose email to Hannes.Tschofenig@gmx.net" title="Compose email to Hannes.Tschofenig@gmx.net"> <i class="bi bi-envelope"></i></a></span> <br> <a class="btn btn-primary btn-sm mt-1" href="mailto:rfc5491@ietf.org?subject=rfc5491" title="Send email to the document authors">Email authors</a> </td> </tr> <tr> <td></td> <th scope="row"> RFC stream </th> <td class="edit"> </td> <td > <img alt="IETF Logo" class="d-lm-none w-25 mt-1" src="https://static.ietf.org/dt/12.28.2/ietf/images/ietf-logo-nor-white.svg" > <img alt="IETF Logo" class="d-dm-none w-25 mt-1" src="https://static.ietf.org/dt/12.28.2/ietf/images/ietf-logo-nor.svg" > </td> </tr> <tr> <td></td> <th scope="row"> Other formats </th> <td class="edit"> </td> <td> <div class="buttonlist"> <a class="btn btn-primary btn-sm" target="_blank" href="https://www.rfc-editor.org/rfc/rfc5491.txt"> <i class="bi bi-file-text"></i> txt </a> <a class="btn btn-primary btn-sm" target="_blank" href="https://www.rfc-editor.org/rfc/rfc5491.html"> <i class="bi bi-file-code"></i> html </a> <a class="btn btn-primary btn-sm" download="rfc5491.pdf" target="_blank" href="https://www.rfc-editor.org/rfc/pdfrfc/rfc5491.txt.pdf"> <i class="bi bi-file-pdf"></i> pdf </a> <a class="btn btn-primary btn-sm" target="_blank" href="https://www.rfc-editor.org/rfc/inline-errata/rfc5491.html"> <i class="bi bi-file-diff"></i> w/errata </a> <a class="btn btn-primary btn-sm" target="_blank" href="/doc/rfc5491/bibtex/"> <i class="bi bi-file-ruled"></i> bibtex </a> </div> </td> </tr> <tr> <td> </td> <th scope="row"> Additional resources </th> <td class="edit"> </td> <td> <a href="https://mailarchive.ietf.org/arch/browse/geopriv?q=rfc5491 OR %22draft-ietf-geopriv-pdif-lo-profile%22"> Mailing list discussion </a> </td> </tr> </tbody> </table> <a class="btn btn-sm btn-warning mb-3" target="_blank" href="https://github.com/ietf-tools/datatracker/issues/new/choose"> Report a datatracker bug <i class="bi bi-bug"></i> </a> </div> <div class="tab-pane mb-5" id="toc-tab-pane" role="tabpanel" aria-labelledby="toc-tab" tabindex="0"> <nav class="nav nav-pills flex-column small" id="toc-nav"> </nav> </div> <div class="tab-pane mb-5 small" id="pref-tab-pane" role="tabpanel" aria-labelledby="pref-tab" tabindex="0"> <label class="form-label fw-bold mb-2">Show sidebar by default</label> <div class="btn-group-vertical btn-group-sm d-flex" role="group"> <input type="radio" class="btn-check" name="sidebar" id="on-radio"> <label class="btn btn-outline-primary" for="on-radio">Yes</label> <input type="radio" class="btn-check" name="sidebar" id="off-radio"> <label class="btn btn-outline-primary" for="off-radio">No</label> </div> <label class="form-label fw-bold mt-4 mb-2">Tab to show by default</label> <div class="btn-group-vertical btn-group-sm d-flex" role="group"> <input type="radio" class="btn-check" name="deftab" id="docinfo-radio"> <label class="btn btn-outline-primary" for="docinfo-radio"> <i class="bi bi-info-circle me-1"></i>Info </label> <input type="radio" class="btn-check" name="deftab" id="toc-radio"> <label class="btn btn-outline-primary" for="toc-radio"> <i class="bi bi-list-ol me-1"></i>Contents </label> </div> <label class="form-label fw-bold mt-4 mb-2">HTMLization configuration</label> <div class="btn-group-vertical btn-group-sm d-flex" role="group"> <input type="radio" class="btn-check" name="htmlconf" id="txt-radio"> <label class="btn btn-outline-primary" for="txt-radio" title="This is the traditional HTMLization method."> <i class="bi bi-badge-sd me-1"></i>HTMLize the plaintext </label> <input type="radio" class="btn-check" name="htmlconf" id="html-radio"> <label class="btn btn-outline-primary" for="html-radio" title="This is the modern HTMLization method."> <i class="bi bi-badge-hd me-1"></i>Plaintextify the HTML </label> </div> <label class="form-label fw-bold mt-4 mb-2" for="ptsize">Maximum font size</label> <input type="range" class="form-range" min="7" max="16" id="ptsize" oninput="ptdemo.value = ptsize.value"> <label class="form-label fw-bold mt-4 mb-2">Page dependencies</label> <div class="btn-group-vertical btn-group-sm d-flex" role="group"> <input type="radio" class="btn-check" name="pagedeps" id="inline-radio"> <label class="btn btn-outline-primary" for="inline-radio" title="Generate larger, standalone web pages that do not require network access to render."> <i class="bi bi-box me-1"></i>Inline </label> <input type="radio" class="btn-check" name="pagedeps" id="reference-radio"> <label class="btn btn-outline-primary" for="reference-radio" title="Generate regular web pages that require network access to render."> <i class="bi bi-link-45deg me-1"></i>Reference </label> </div> <label class="form-label fw-bold mt-4 mb-2">Citation links</label> <div class="btn-group-vertical btn-group-sm d-flex" role="group"> <input type="radio" class="btn-check" name="reflinks" id="refsection-radio"> <label class="btn btn-outline-primary" for="refsection-radio" title="Citation links go to the reference section."> <i class="bi bi-arrow-clockwise"></i> Go to reference section </label> <input type="radio" class="btn-check" name="reflinks" id="citation-radio"> <label class="btn btn-outline-primary" for="citation-radio" title="Citation links go directly to the cited document."> <i class="bi bi-link-45deg me-1"></i>Go to linked document </label> </div> </div> </div> </div> </div> </div> </div> <script type="text/javascript"> var _paq = window._paq || []; _paq.push(['disableCookies']); _paq.push(['trackPageView']); _paq.push(['enableLinkTracking']); (function() { var u="//analytics.ietf.org/"; _paq.push(['setTrackerUrl', u+'matomo.php']); _paq.push(['setSiteId', 7]); var d=document, g=d.createElement('script'), s=d.getElementsByTagName('script')[0]; g.type='text/javascript'; g.async=true; g.defer=true; g.src=u+'matomo.js'; s.parentNode.insertBefore(g,s); })(); </script> <noscript><p><img src="//analytics.ietf.org/piwik.php?idsite=7" style="border:0;" alt="" /></p></noscript> <script>(function(){function c(){var b=a.contentDocument||a.contentWindow.document;if(b){var d=b.createElement('script');d.innerHTML="window.__CF$cv$params={r:'8e9b98160c8b464f',t:'MTczMjgwOTg3MC4wMDAwMDA='};var a=document.createElement('script');a.nonce='';a.src='/cdn-cgi/challenge-platform/scripts/jsd/main.js';document.getElementsByTagName('head')[0].appendChild(a);";b.getElementsByTagName('head')[0].appendChild(d)}}if(document.body){var a=document.createElement('iframe');a.height=1;a.width=1;a.style.position='absolute';a.style.top=0;a.style.left=0;a.style.border='none';a.style.visibility='hidden';document.body.appendChild(a);if('loading'!==document.readyState)c();else if(window.addEventListener)document.addEventListener('DOMContentLoaded',c);else{var e=document.onreadystatechange||function(){};document.onreadystatechange=function(b){e(b);'loading'!==document.readyState&&(document.onreadystatechange=e,c())}}}})();</script></body> </html>

CINXE.COM

RFC 5491 - GEOPRIV Presence Information Data Format Location Object (PIDF-LO) Usage Clarification, Considerations, and Recommendations