Points of Interest SWG

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Adapted from the POI SWG Charter


The work of the committee will be carried out primarily by email and conference calls, every two weeks on Thursdays at 9am eastern, with face-to-face meetings during each of the OGC TC meetings.

Points of Interest

A “point of interest” (POI) is a location for which information is available. A POI can be as simple as a set of coordinates, a name, and a unique identifier, or more complex such as a three-dimensional model of a building with names in multiple languages, information about opening and closing hours, and a civic address. POI data has many applications, including augmented reality browsers, location-based social networking games, geocaching, mapping and navigation systems.

In practice, POIs are usually those places that serve a public function. As such, POIs generally exclude facilities such as private residences, but include many private facilities that seek to attract the general public such as retail businesses, amusement parks, industrial buildings, etc. Government buildings and significant natural features are POIs as well.

Considering how ubiquitous the need for POI information is, surprisingly international standardization efforts have been so few up to now. In many ways, one could consider POIs a most fundamental requirement of any spatial data infrastructure. We also see their importance in the commercial sector for navigation applications and social networks. In fact, Facebook has made location such an integral part of their data model that every activity a user does can be tagged with location, weaving places of interest seamlessly into the fabric of their social platform.

OGC has had a gazetteer best practice specification for years, but it has not seen widespread adoption. This is odd because as with POI data, the need for gazetteers touches every industry. Most obviously, all personal navigation systems have at their information core a gazetteer. Further, academics, scientists, and business information analysts also have strong needs to query for standard, structured ways to manage basic place information. Perhaps the lack of a single, unified data model has hampered the adoption of the gazetteer as a service model. Having a POI data model could play a significant role in accelerating the success of the gazetteer service model.

Purpose of the Standards Working Group

The purpose of the POI SWG is to produce a version 1.0 encoding standard of points of interest data that includes an abstract data model and JSON and XML Schema implementations of that data model.

Scope of Work

The SWG shall review, edit and expand upon the draft specification developed by the World Wide Web Consortium (W3C) POI Working Group to produce a version 1.0 implementation standard. The review shall be both a technical and editorial review.

As the W3C work already uses GML 3.3 compact encoding for the geometries of a POI, it is not expected that further harmonization with the OGC standards baseline is necessary.

The items that need to be addressed by the SWG include:

  1. Update to conform to the latest OGC document directives:
  • While not mandated for an encoding specification the SWG will conform to the Modular Specifications Policy as appropriate.
  • Add a JSON encoding, with particular attention paid to considering GeoJSON
  • Add an abstract test suite.
  • Validate all schemas and examples.
  • Study the interactions between service model and data encoding approaches to POI and gazetteer functions.
  • Address any other technical and/or editorial issues that arise during the review period.
  • The SWG will develop the specification in a public repository in GitHub, carry out its document review and comment process using those tools provided in that system.

    What is out of scope?

    Positioning this encoding standard in a web services environment is out of scope.

    Developing encodings other than those described in this Charter or in the World Wide Web Consortium draft specification is out of scope.

    Specifying civic addresses, other than adopting an existing specification such as VCARD, is out of scope.

    Specification of a formal metadata model is out of scope, although this is recognized as an important item for future work.

    Change requests and comments submitted through GitHub as well as through traditional processes identified in the Policy and Procedures shall be addressed.  Any items suggested through emails, vocal discussions, etc. will be outside of the scope of this SWG.

    Existing Work as a Starting Point

    World Wide Web Consortium POI Working Group

    The starting point for this implementation standard shall be prior work begun, but abandoned, by the W3C with OGC participation, described at http://www.w3.org/2010/POI/. This effort generally conforms to the ISO information model as described in 19112 (see below), although it has fewer required properties, and extends that model in some very important ways that reflect its focus on the architecture of the Web. In terms of similarities with the ISO and OGC standards, POI’s primary properties for gazetteer items are a name and a geographic identifier (location) that can be either direct, indirect, or both. POI expands upon this model with a mandatory URI-based globally unique ID, along with Categories and Links.

    ISO 19112 – Spatial referencing by geographic identifiers

    ISO 19112 describes a basic framework for describing items in a gazetteer. It links “indirect” geographic references, which are things like addresses and town names, to “direct” references, which are geographic coordinates. In other words, ISO 19112 defines a standard information model for saying that a place is located at a specific position on the Earth. The standard goes far beyond that baseline though. Positions on the Earth can be described in any number of ways, such as by a rough bounding box, an exact polygon boundary, or a point in the center of the place. ISO 19112 also describes a host of metadata that can be associated with the place, such as the administrative agency responsible for the data, in what part of the world the data should be used, and in what time period it’s valid.

    ISO 19155:2012 – Place identifier

    In ISO 19155, the identifier of a place is referred to as a Place Identifier (PI). A single “place” may be identified using several separate Place Identifiers.

    Place descriptions are used for information retrieval. In reality, those identifiers often refer to the same place. Currently these relationships are difficult for machines to correctly distinguish, which impedes the discovery and retrieval of information. The conceptual architecture and reference model defined in ISO 19155 provides a mechanism for solving these problems.

    When implemented, this architecture would enable the access and sharing of place descriptions using the Place Identifier as the standardized method.

    Within the reference model, place descriptions are defined using a PI. A PI consists of a reference system (RS), a value, and the valid temporal period of that value.

    OGC Gazetteer Service – Application Profile of the Web Feature Service

    Using the ISO standard as a foundation, the Open Geospatial Consortium (OGC) defined a gazetteer service in 2006. It takes the information model for gazetteer data from ISO 19112, and the web service information request model from OGC’s Web Feature Service (WFS) to define the Gazetteer Service - Application Profile of the Web Feature Service Implementation Specification. This service is a “best practices document” -- not yet a formal international standard – but has recently advanced towards full standard status. The OGC gazetteer service implements the ISO abstract data model in XML using the OGC Geography Markup Language (GML) standard, and describes how to make web requests for information from the gazetteer using WFS.

    Determining when the Work of the SWG has been Completed

    This SWG shall be dissolved after the following three milestones have been achieved:

    • The SWG has produced a V1.0 POI candidate standard.
    • SWG membership approves a recommendation to submit the document to the TC for consideration as an OGC Adopted Standard.
    • The candidate standard has been approved by the OGC Technical and Planning Committees as an Adopted OGC standard.

    Description of deliverables

    There shall be three deliverables:

    • Points of Interest (POI) Core Encoding Specification version 1.0.
    • Points of Interest (POI) XML Encoding Specification version 1.0.
    • Points of Interest (POI) JSON Encoding Specification version 1.0.

    IPR Policy for this SWG

    The IPR Policy for the Points of Interest SWG will be RAND and Royalty Free.

    Anticipated Audience

    Any organization that has a requirement for information sharing of points of interest data, such as organizations providing gazetteers, historical place name researchers, and navigation data providers.

    Other informative information about the work of this SWG

    Similar or applicable standards work (OGC and elsewhere)

    The following standards and projects may be relevant to the SWG's planned work, although none currently provide all the functionality anticipated by this committee's deliverables:

    Charter Members

    • Ashley Holt (NGA)
    • Peter Cotroneo (Ordnance Survey)
    • Chris Body (Dept. of Resources, Energy, Tourism Australia)
    • Jiyeong Lee (University of Seoul)
    • Ed Parsons (Google)
    • Marie-Françoise Voidrot-Martinez (Meteo France)
    • Clemens Portele (Interactive Instruments)
    • Doug Caldwell (USACE)
    • Pedro Goncalves (Terradue Srl)
    • Krzysztof Janowicz (NCGIA)