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Network Working Group C. Reed Request for Comments: 5165 Open Geospatial Consortium Category: Informational April 2008

          A Uniform Resource Name (URN) Namespace for the
                  Open Geospatial Consortium (OGC)

Status of This Memo

 This memo provides information for the Internet community.  It does
 not specify an Internet standard of any kind.  Distribution of this
 memo is unlimited.


 This document describes a Uniform Resource Name (URN) namespace that
 is engineered by the Open Geospatial Consortium (OGC) for naming
 persistent resources published by the OGC.  The formal Namespace
 IDentifier (NID) is "ogc".

1. Introduction

 The Open Geospatial Consortium (OGC) is a voluntary consensus
 standards organization.  Founded in 1994, the OGC produces many kinds
 of technical documents, including: standards, working drafts,
 technical reports, discussion papers, and XML schemas.  The OGC
 wishes to provide persistent, location-independent Identifiers for
 these resources.  Further, a number of OGC standards and application
 schemas of OGC standards are now used and/or referenced by standards
 specifications from other standards organizations, including OASIS,
 the IETF, IEEE, ISO, and OMA.
 The OGC core mission is to develop spatial interface and encoding
 specifications that are openly available and royalty free.  Products
 and services that conform to OGC interface specifications enable
 users to freely exchange and process spatial information across
 networks, computing platforms, and products.  Interoperability in
 such an environment is facilitated by the use of a system of
 persistent identifiers that are global in scope.  The OGC is the only
 standards organization whose mission is specifically focused in
 interfaces and encodings for geospatial content and services.
 Motivated by these concerns, the OGC would like to assign formal URNs
 to published resources in order to provide persistent, location-
 independent identifiers for them.  The process for registering a
 namespace identifier is documented in RFC 3406 [2].

Reed Informational [Page 1] RFC 5165 A URN Namespace for the OGC April 2008

 The official IANA registry of URN namespaces is available online:
 2.  URN Specification for "ogc" NID
 Namespace ID:
 Registration Information:
    Registration Version Number: 1
    Registration Date: 2007-08-16
 Declared registrant of the namespace:
    Open Geospatial Consortium, Inc. (Headquarters)
    35 Main Street, Suite 5
    Wayland, MA 01778-5037, USA
    c/o Carl Reed (
 Declaration of syntactic structure:
    The Namespace Specific String (NSS) of all URNs that use the "ogc"
    NID will have the following structure:
    where the "OGCresource" is a US-ASCII string that conforms to the
    URN syntax requirements [1] and defines a specific class of
    resource type.  Each resource type has a specific labeling scheme
    that is covered by "ResourceSpecificString", which also conforms
    to the naming requirements of [1].  The only exception is that the
    character ":" shall not be used as part of the "OGCresource"
    string.  This is to avoid possible confusion.  Further,
    "OGCresource" is case sensitive.
    The OGC maintains a naming authority, the OGC Naming Authority
    (ONA), that will manage the assignment of  "OGCresources" and the
    specific registration values assigned for each resource class.
 Relevant ancillary documentation:
    The OGC Naming Authority (ONA) provides information on the
    registered resources and the registrations for each.  More
    information about ONA, the registration activities, and procedures
    to be followed are available at:

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    An operational OGC URN "resolver" is available at  The resolver provides a registry of the
    currently member approved OGC URN's used in currently approved and
    implemented OGC standards.
    The OGC Naming Authority is a permanent OGC resource.  The
    documents and related OGC URN resources, such as the URN resolver,
    have stable URLs.  The ONA reference is
    There are a number of OGC Best Practice and Standards documents
    that define member agreements on the definitions for "OGCresource"
    and ResourceSpecificString.
 Identifier uniqueness considerations:
    The ONA manages resources using the "ogc" NID and will be the
    authority for managing the resources and subsequent strings
    associated.  In the associated procedures, ONA will ensure the
    uniqueness of the strings themselves or shall permit secondary
    responsibility for the management of well-defined sub-trees.
    The OGC may permit the use of experimental type values that will
    not be registered.  As a consequence, multiple users may end up
    using the same value for separate uses.  As experimental usage is
    only intended for testing purposes, this should not be a real
 Identifier persistence considerations:
    The OGC provides clear documentation on a number of the registered
    uses of the "ogc" NID.  Additional uses developed by the OGC
    membership in the future will be first approved by the ONA and
    then by the entire OGC voting membership.  This is the normal
    process for all OGC documents that become OGC standards or other
    permanent resources for use by the community.
    The OGC Naming Authority maintains a permanent registry of
    approved uses.  This resource is structured such that each
    "OGCresource" has a separate description and registration table.
    The registration tables and information are published and
    maintained by the ONA on the OGC web site.

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 Process of identifier assignment:
    The ONA uses the approved OGC standards policies and procedures
    for discussion, approval, and registration of each type of
    resource maintained [3].
    Each such resource may have three types of registration
       1) Registered values associated with OGC specs or services
       2) Registration of values or sub-trees to other entities
       3) Name models for use in experimental purposes
 Process for identifier resolution:
    The namespace is not listed with a Resolution Discovery System
    (RDS); this is not relevant.
 Rules for Lexical Equivalence:
    No special considerations except as noted in the declaration of
    syntactic structure; the rules for lexical equivalence of [1]
 Conformance with URN Syntax:
    No special considerations.
 Validation mechanism:
    None specified.  URN assignment will be handled by procedures
    implemented in support of ONA activities.

3. Examples

 The following examples are representative URNs that have been
 assigned by the ONA.
 Defines the URN to be used to identify version 3.0.0 of an OGC
 specification document for the Geography Markup Language in the OGC
 document archives.

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 Defines the URN to be used for an application to specify the specific
 service type for an OGC Catalogue service.
 This is the URN literal to reference the definition of the Coordinate
 Reference System (CRS) with code 26986 that is specified in version
 6.3 of the EPSG database [4].

4. Namespace Considerations

 There is currently no available namespace that will allow the OGC to
 uniquely specify and access resources, such as schemas and
 registries, that are required by organizations implementing OGC
 standards.  There is also a need for other standards organizations,
 such as OASIS and the IETF, to be able to access OGC specific
 The geospatial and location services industry will benefit from the
 publication of this namespace by having more permanent and reliable
 names for the XML namespaces, schema locations, standards document
 reference, and other document artifacts required for implementation
 of an OGC standard.
 The OGC members considered the use of other existing NIDs, such as
 those for OASIS and OMA.  However, the semantics for geospatial
 content and services have a number of unique characteristics, such as
 the expression of coordinate reference systems.  The URN syntax used
 by OASIS and OMA do not support the necessary elements to express the
 full semantics used in and by the geospatial community.

5. Community Considerations

 Both the traditional geospatial and location services industry as
 well as the broader IT community will benefit from the publication of
 this namespace by providing permanent and reliable names for the XML
 namespaces, schema locations, catalogues registries, and other
 document artifacts required for implementation of an OGC standard.
 We desire these resources to be freely and openly available as a set
 of community resources.  Not only can OGC members identify and submit
 new proposals for additional resources, but any individual or
 organization can make a contribution by submitting a proposal to the
 OGC for consideration by the ONA.  Normal OGC standards discussion
 and approval processes will be used to process any new community

Reed Informational [Page 5] RFC 5165 A URN Namespace for the OGC April 2008

 Since 2003, the OGC membership has been developing expertise in using
 the OGC URN.  The knowledge and experience gained through
 implementation experiments and a variety of operational test beds
 contributed to the current OGC URN specification.  The knowledge is
 documented in OGC documents (above) as well as an operational OGC URN
 resolver.  Work is also underway on a publicly accessible OGC URN
 registry.  These resources are necessary for a number of reasons,
 including the fact that numerous agencies and organizations, such as
 NATO and NGA, have mandated a procurement policy that requires OGC
 standards and their related OGC URNs.

6. Security Considerations

 There are no additional security considerations other than those
 normally associated with the use and resolution of URNs in general.

7. IANA Considerations

 This document defines a URN NID registration of "ogc", which has been
 entered into the IANA registry located at

8. Normative References

 [1] Moats, R., "URN Syntax", RFC 2141, May 1997.
 [2] Daigle, L., van Gulik, D., Iannella, R., and P. Faltstrom,
     "Uniform Resource Names (URN) Namespace Definition Mechanisms",
     BCP 66, RFC 3406, October 2002.
 [3] OGC Technical Committee Policies and Procedures, Version 3,
     October 1, 2007. Available (online):
 [4] "Definition identifier URNs in OGC namespace" Version 1.1 Arliss
     Whiteside, An OGC Best Practices, August 2006. Available

Author Address

 Carl Reed, PhD
 Chief Technology Officer
 Open Geospatial Consortium, Inc.
 35 Main Street, Suite 5
 Wayland, MA 01778-5037, USA

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 contained in BCP 78, and except as set forth therein, the authors
 retain all their rights.
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