July 27th, 2011
The OGC Announces GML 4.0 (Geography Markup Language) Workshop

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The OGC and the GML Working Group invites interested parties to attend a one-day workshop on GML 4 on September 19th in Boulder, Colorado. The workshop is organized as part of the September OGC TC meeting, but is open to non-OGC members.

The current approved version of GML is GML 3.2, which is identical to ISO 19136:2007. After a public request for change requests in 2008, the OGC members have processed several of these change requests and plan to release GML 3.3 later this year. This version will be specified as an extension to GML 3.2 and be fully backwards compatible with GML 3.2.

Many communities use the current versions of GML. Creating a version 4 is something not lightly undertaken. Besides a number of pending change requests to be considered by the GML Working Group, GML 4 is also required to comply to the new modular specification policy of OGC. One of the key challenges of the revision will be the identification of the modular structure and how fine-grained it should be.

Before starting work on GML 4, the GML Working Group wants to have a clear idea, if there is demand for such a version, what the goal and characteristics of this new version should be and how OGC can best address the requirements of existing and potential users. In order to get a better understanding of the needs and expectations of user communities and developers both inside and outside of the OGC membership, the workshop will be open to all members of the OGC and also to non-OGC-members who are interested. Representatives from other OGC Working Groups, existing user communities, software developers and ISO/TC 211 members are encouraged to attend.

The goal of the workshop is to get input and guidance from the GML user community for the development of GML 4. The workshop should result in a set of principles the GML Working Group can use as guidance in the process of designing the next version of the standard.

Interested parties are encouraged to provide statements in advance, outlining their opinion on the subject. These statements will be used to prepare the meeting so that we can get maximum use out of the workshop. Statements could address issues like:

• Positioning of GML 4. The current understanding is that GML 4.0 should not replace GML 3.2/3.3 and that existing community encodings with specific application support will likely continue to use GML 3.
• Key features of GML 4 that would justify developing and publishing a new version of GML.
• The modularization of GML, making it easier to pick and choose parts of GML that are relevant in a certain context. For example, the current schema could be structured in about 20 modules, generally along the lines of the current schema documents. Alternatively, a more fine-grained structure could be designed and “profiles” (defined, for example, in a standard or by a community) would then be aggregations of these.
• Making GML easier to implement and/or easier to use.
• Solving current problems with GML that prevent successful use/implementation.

More information about the workshop will be made available on this wiki, including information how to register for the event and how to post and view statements.