Re: [emergency] Groups - AboutNameSpaces.pdf uploaded

[Robin Cover <robin@oasis-open.org>]

On Wed, 9 Mar 2011, Werner.Joerg@iem.com wrote:

> Please review these notes about name spaces and e-mail your feedback to the
> list.
>
> Your help is greatly appreciated!
>
> -- Werner Joerg
>
> The document named AboutNameSpaces.pdf has been submitted by Werner Joerg
> to the OASIS Emergency Management TC document repository.
>
> Document Description:
> As we were preparing requests for OASIS templates for Work Products (see
> "Work Product Registration / Template Request" at
> http://docs.oasis-open.org/templates/TCAdminRequests15-10-2010.html),
> questions about naming conventions have emerged and it has been determined
> that we need to clarify issues relating to name spaces in particular,
> before we can finalize the submissions.
> The EM TC has tasked me with presenting a proposal for naming conventions
> that could be applied consistently across all EM Work Products - this
> document captures my notes for your review and feedback.
>
> View Document Details:
> http://www.oasis-open.org/committees/document.php?document_id=41402
>
> Download Document: 
> http://www.oasis-open.org/committees/download.php/41402/AboutNameSpaces.pdf

------------------------- Robin now writes:

I appreciate the attention that Werner and other TC members are giving
to the details of naming.  Experience to date shows that with careful
planning and design of names and namespaces, for extensibility and
other goals, one prepares a much smoother road ahead for spec development.

I'm sending Werner an off-list note about one nit (WP Title/Name), but
that's fairly inconsequential.

In this note I would like to encourage the TC members involved in
the document engineering to seriously consider migration to the
use of HTTP scheme URIs for identification of XML namespace
names (rather than using URNs).

Most of the arguments I would make are actually made in a recent
publication from the Open Geospatial Consortium (OCG), which
includes apparently a June 17, 2010 decision to approve:

   "OGC should immediately mandate the use of http URI for
    identification of persistent OGC resources, in preference
    to URNs"

The document is:

"OGC Identifiers: The case for http URIs"
http://portal.opengeospatial.org/files/?artifact_id=39467
10-124r1_OGC_Identifiers_-_the_case_for_http_URIs.pdf

Excerpt: "According to the current policy either URNs or
http URIs may be used in specifications [OGC-NA]. However,
the use of http URIs (a) resolves some deployment
challenges and (b) provides an opportunity for easier
engagement with broader communities. So OGC should now
consider taking the next step, and mandate the use of http
URIs for persistent identifiers in OGC standards. This
white paper discusses a number of issues related to this
proposal. [2]

I have copied out the text of the document's Summary [1]
which summarize the major considerations and the paper's
recommendations.

Example in use: http://www.opengis.net/gml/
HTTP scheme URI identifying the XML namespace name
for 'GML - the Geography Markup Language'

Net discussions about the technical merits/demerits of using
HTTP Scheme URIs vs URNs for namespace names are still
alive, but anecdotally, from my POV, there is a strong
industry trend in the direction of using HTTP Scheme URIs.
The advantages are too significant to ignore.

One consideration not elaborated in the OGC document
summary is that the recommended (required at OASIS)
namespace document which lives at the end of a
namespace URI (HTTP scheme URI used to identity an
XML namespace name) provides a very natural means
to present to a user some description of the resources
related to any namespace name: all you do is "click."

Furthermore, the namespace document provides a
metadata-level document that can be updated/augmented
after the formal publication of a specification, to
reflect important information.  We allow these namespace
documents, not formally a "part" of an approved
specification, to be changed as the need arises; the
fixed specification itself cannot be changed.

Additionally, we encourage the use of identifier strings
based upon (base) XML namespace names for non-information resources
and the "for free" resolution to documentation is again
very efficient for providing simple-click documentation.
Viz., Non-information resources using identifiers
associated with XML namespaces may be based upon
any HTTP scheme URI XML namespace declared by the
TC (i.e., identifiers for named properties, functions,
dialects, faults, actions, or any named message types).

For further information on XML namespaces in OASIS
specifications, see:

http://docs.oasis-open.org/specGuidelines/ndr/namingDirectives.html#xml-namespaces
[older:]
http://docs.oasis-open.org/specGuidelines/namingGuidelines/metadata.html#declaredNamespace
http://docs.oasis-open.org/specGuidelines/namingGuidelines/resourceNaming.html#NamespaceDesign
http://docs.oasis-open.org/specGuidelines/namingGuidelines/resourceNamingCommentary.html#urnResolution
http://docs.oasis-open.org/specGuidelines/namingGuidelines/resourceNamingCommentary.html#nsTypes4x
http://docs.oasis-open.org/specGuidelines/namingGuidelines/resourceNamingCommentary.html#uri-overloading

-- 

Robin Cover
Interim TC Administrator
OASIS, Director of Information Services
Editor, Cover Pages and XML Daily Newslink
Email: robin@oasis-open.org
Staff bio: http://www.oasis-open.org/who/staff.php#cover
Cover Pages: http://xml.coverpages.org/
Newsletter: http://xml.coverpages.org/newsletterArchive.html
Tel: +1 972-296-1783

=============== References:

[1] OGC document OGC 10-124r1 - "OGC Identifiers: The case for http URIs"

7. Summary and recommendations

Given that:

- In order to support SDI deployment, resources provided
   by OGC for ongoing use should have well-governed,
   maintained, persistent identifiers
- A http URI or a URN is a text string, and may be used
   for persistent identification
- A http URI, unlike a URN, is implicitly bound to a
   resolver service known to all web-clients. Documents
   that include references expressed as http URIs can be
   consumed by generic web applications.
- Use of http URIs to identify OGC resources is likely
   to increase the impact of OGC in the mass market

1. OGC should immediately mandate the use of http URI for
identification of persistent OGC resources, in preference
to URNs. (Approved June 17, 2010)

Note that this recommendation applies to identifiers for
resources that are governed by OGC, which are intended
to be persistent. There is no obligation on any other
organization, including those using spatial data
infrastructures based on OGC technology. The use http
URIs for transient resources may be inappropriate.

To support this:

2. OGC should carefully manage (maintain for the long term)
the http://www.opengis.net domain and identifiers in this
domain

3. OGC should ensure that suitable representations of
resources with identifiers in the domain
http://www.opengis.net are provided through the http
protocol. This includes redirection and content negotiation,
where appropriate.

[2] OGC document metadata

"OGC Identifiers: The case for http URIs"
http://portal.opengeospatial.org/files/?artifact_id=39467
10-124r1_OGC_Identifiers_-_the_case_for_http_URIs.pdf

OGC 10-124r1
Copyright 2010 Open Geospatial Consortium, Inc.
Open Geospatial Consortium Inc.
Date: 2010-07-15
Reference number of this document: 10-124r1 OGC
Name of this document: http://www.opengis.net/doc/WhitePaper/Identifiers/1.0
Category: OpenGIS White Paper
Editor: Simon Cox

Download from:
White Papers: Documents describing official positions of the
Open Geospatial Consortium, Inc.
http://www.opengeospatial.org/pressroom/papers
  - http://portal.opengeospatial.org/files/?artifact_id=39467 (PDF)
  - http://portal.opengeospatial.org/files/?artifact_id=39467&format=doc (MS Word)

See also on URNs:
Definition identifier URNs in OGC namespace
http://portal.opengeospatial.org/files/?artifact_id=30575


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