Task #2381

Propose ToR for a subgroup around GML

Added by Michael Lutz over 5 years ago. Updated over 4 years ago.

Status:Work in progressStart date:16 Mar 2015
Priority:NormalDue date:
Assignee:Michael Lutz% Done:


Proposed change or action:


Placeholder for a task on developing ToR for a subgroup around GML

MIWP-xx_GML.docx (30.4 KB) Michael Lutz, 24 Nov 2015 10:18 am

Related issues

Related to MIG-T - MIWP-Action #2133: MIWP-11: Simplification and clarification of GML encoding... Under elaboration 01 May 2014
Related to MIG-T - MIWP-Action #2134: MIWP-12: Clarification of UML-to-GML encoding rules Under elaboration 01 May 2014
Related to MIG-T - MIWP-Action #2420: MIWP-18b XML schema maintenance Proposed 27 Apr 2015


#1 Updated by Michael Lutz over 4 years ago

  • Status changed from New to Work in progress
  • % Done changed from 0 to 40

As discussed in the previous MIG-T meeting and in preparation of the MIG-T meeting in Rome, please find attached a proposal for a new MIWP action related to GML/xml schemas. It tries to reflect the recurring discussions around simplification (aka "flattening") of xml schemas (NB not simplification of the data models) and the missing client support for complex features in xml schemas.

If endorsed, this action would replace the currently proposed actions MIWP-11 and 12, and possibly MIWP-18b.

Please add your comments and suggestions on the proposed action here. 

#2 Updated by Paul Hasenohr over 4 years ago

Dear Michael,


Thank you very much for having drafted this proposal on which I have some comments.

My view on this topic is that we should not mix the "flattening" of the schemas and the tool development. Considering that we are in the middle of the implementation of INSPIRE, I am also very reluctant to see the MIG start working on new schemas because this is what the simplification implies: creating new schemas which will have again to be validated and in which bugs will be discovered as MS use them.

Also this need for simplification comes from the lack of clients able to consume resources modelled according to the INSPIRE data models. If we address the lack of clients, we are addressing the issue in my view.

Lastly the tools have to be able to work with extended schemas.


In conclusion, the only XML related activity I would keep in this work package is the identification of the XML/GML subset needed by INSPIRE which has to be supported by any software aiming at consuming INSPIRE data. In terms of proposed action, I would propose to review the status of INSPIRE consumption and usage in various software and underlying libraries, identify the gaps, maintain a repository of planned/on-going activities aiming at closing these gaps. There is some overlap with the work proposed by Robin under Are3na but I think having it as a MIG action would increase its visibility and importance.


Best regards,


#3 Updated by Christian Ansorge over 4 years ago

Dear colleagues,

Sorry for my reply which comes now a bit too late. I can just underline what Paul said and add to it.

I am also very sceptical towards the "flattening" issue, despite acknowledging that this is a discussion we have in the community for several years. I have some points to add:

  • We are in the process of implementing and stakeholders slowly start looking into these complex type GML schemas. If we now “start discussing” simplifications of the schemas every activity related to the current schemas will stop and stakeholders will wait for the outcomes of this discussion. Taking into account some iterations until potentially simplified schemas will be known, stable and supported by solution providers it will take years and present a risk for the implementation of INSPIRE.
  • To use flattened schemas is possible already now, as the current suggested schemas are not legally binding. You might provide SF schemas and guidelines to not further jeopardize the interoperability. Still, by using complex and simple GML in a mixed environment interoperability is questionable and with this a core objective of the INSPIRE Directive.
  • If discussions about further simplified schema variations (aka flattening) are still considered as absolutely necessary it shall be limited to identify potential simplification which not affect the UML models and IR on ISDSS! Changes in the UML models and the IR would result in wider changes (TG or even legal framework) which bear the risk to further delay the implementation of the INSPIRE Directive.

I fully support the conclusion of Paul and consider it as contradictory to discuss the further development of tools supporting complex GML consumption and simplification of the schemas at the same time by the same working group. In my opinion the full should be on the continuation of the work on the complex GML provision and consumption side.

Just my personal opinion on this topic.




PS: There is no attachment. 

#4 Updated by Michael Lutz over 4 years ago

  • File MIWP-xx_GML.docx added

Paul, Christian,

thanks for your comments and for spotting I didn't actually attach the proposed action description (attached now: MIWP-xx_GML.docx).

I agree to the risks you describe related to the "flattening discussion". But my fear is that if we exclude this topic, it will be popping up again and again (as it has over the past year) and there will be no factual basis for these discussions. This was one of the reasons for includingto topic - to "give this discussions a home" and have thematic and GML experts discuss what the use cases and needs for such "flattened" schemas really are and (if there are any) how the simplication could be achieved in a common way. 

I hope the action description clearly describes that any simplifcation discussion should be driven by thematic use cases (coming from MIWP-14 and the Thematic Clusters), and that it is by no means aimed at simplifying the conceptual model (see "Scope").

#5 Updated by Michael Lutz over 4 years ago

  • File deleted (MIWP-xx_GML.docx)

#6 Updated by Michael Lutz over 4 years ago

#7 Updated by Marc Leobet over 4 years ago

We have some problems with that discussion. In France, we consider that we have no users for the full INSPIRE data models. And it is not rational to produce things without users, is it?

So we need to flattened data models to deliver datasets to public authorities.

We need to do it in an European framework to keep one important point in INSPIRE, eg. interoperability in the Union. That is specially important for Annex I & II themes which gather reference datasets, and for reporting data (we have here a strong use case).

To be efficient, we need to flattened data models following some specific use cases, to be sure to build something for users in the whole Union.

The "Better Regulation" initiative of Junker's Commission gives the opportunity to look back to the Regulation with new eyes (that is, to change it). Even without that, we said in London's meeting that we could do it with Enterprise architect and be compliant. The lack of cardinality in the Regulation opens the opportunity to change many things too. So, from our point of view, "to be compliant with the directive" is not so obvious.

Our thought is we do not need to work on tools, specially if ARE3NA does the job. We need maybe to be smarter with the models to be able to produce them in Annex I & II, where data producers are national organisations, and share these data in the simplest way for users, without hoping change their tools.

Best regards


#8 Updated by Alex Ramage over 4 years ago

Peter Parslow has asked me to contribute this

Peter wishes to endorse the idea of simplificatin.  He is concerned that INSPIRE stalls at this stage, because some of the things we’re pushing for cannot be used. Basically, I would prefer getting the stuff that can be simple to work, in order to prove the value.

You may be interested to see the results of what we have done at Ordnance Survey (the UK National Mapping Agency)  in looking at really simple GML: just published at http://www.ordnancesurvey.co.uk/about/governance/policies/gml-design.html

Alex Ramage

#9 Updated by Michael Lutz over 4 years ago

The proposal was discussed at the 25th_MIG-T_meeting, and it was agreed to revise the proposal based on the discussions at the meeting [Action Michael Lutz].

#10 Updated by Michael Lutz over 4 years ago

This action should be included in the update of the MIWP (probably under the working area "fitness for purpose").

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