The Harmonized Model

1. The Harmonized Model John R. Herring Convener Harmonized Model Maintenance Group

2. One of the defects of all philosophers since Plato is that their inquiries … proceed on the assumption that they already know the conclusion to be reached. History of Western Philosophy Bertrand Russell, 1946

3. References Text (avoid “cookbooks”- too application specific) • The Unified Modeling Language Reference Manual — James Rumbaugh, Ivar Jacobson, Grady Booch — Addison-Wesley (2nd edition, 2005) Specifications www.omg.org, www.opengeospatial.org • OMG Unified Modeling Language (OMG UML), Infrastructure • OMG Unified Modeling Language (OMG UML), Superstructure • OGC 08-131r3 The Specification Model — A Standard for Modular specifications

4. Purpose of the Harmonized Model • Harmonize ISO TC 211 standards http://www.isotc211.org/pow_all.htm • Define a common object-oriented vocabulary • Provide a common basis for implementations • INSPIRE http://inspire.jrc.ec.europa.eu • SEE Grid (solid earth environment grid) • Two inherent logical layers: • Conceptual – root of interoperability • Implementation – root of plug-n-play

5. HMMG Home —http://www.isotc211.org/hmmg/HTML/root.html Links to – • Model data download  • Dependency document. • An HTML view of the Harmonized Model  • Publicly readable “subversion” repository from CSIRO’s SEE Grid web site. • Version of all parts, standards and work in progress. • Refreshed multiple times daily.

6. What the Harmonized Model is • A UML model defined (in pieces) by the official editions of ‘every’ ISO TC 211 standard • Through various human errors, there are some problems. • The HMMG has only limited authority to fix these • The Model shall match the documents • Minor fixes are done to align the model with the documents • Other problems are referred to “leads” and may result in corrigendum or other fixes.

7. UML in the HM • See Reference Manual cited • Is not a graphics editor • Is a set of formal graphics languages with well-specified meanings and interpretations • Can be some of many things: • Ontology, object design, resource design (REST), process design, system architecture • Well governed system; rules of use, flexible but strict • Layers of model and metamodel, abstractions: ’09, ’10 • Compliance can be loose or tight: ’07, ‘36

8. Model procedures with repository • Edited with Enterprise Architect in (a local copy of) the Harmonized Model (to track GUIDs) – always! • Stored in a “subversion” repository at JRC. • Stored as XMI, each document, published edition – linkages by GUID, not names which may change • Management is done by EA and Subversion • New EA commands: check-out, check-in, refresh (often) • By document editor, or HMMG approved staff • Repository can “recover” the state after any transaction, from any date, state of model

9. Basic procedure with repositories Repository Local Copy Check-out Edit … Transaction Edit Repository Local Copy Check-in

10. Model procedure using copies • Editor begins with a new copy of the harmonized model • New package is created for each document/edition • Editor periodically (monthly?) posts his documents model to the HMMG • HMMG does a quick merge, update and post • Editor retrieves new copy of his doc in HM (all other documents are refreshed to current state)

11. Some limitations • Nothing changes unless the package is checked out before and checked in after (commits a transaction) • An editor should only check out his document • Elements in XMI are identified and linked only by GUIDs, globally unique identifiers • GUIDs enable round tripping of the XMI at any granularity (one package to whole model) • Multiple versions of same document mean no name uniqueness (especially within a series)– all linkages are by GUID

12. The Future — Direct repository use • Currently editions are posted through the HMMG leads, editors work in copies of the model • In the future, editors will access their own documents in the repository – transactions through local copies • The repository procedures will keep them from changing anything they do not own • Subversion tracks all changes, records all states and which user does what.

13. Known Issues (under work / debate) • Unit of reuse (OGC ‘Modular specification policy’) • Unit of reuse in a standard is the conformance class • Unit of reuse in a UML model is the package • In the future, UML packages in the harmonized model should respect conformance class boundaries • Direct Access to repository by editors • Plans to create an “partially editable mirror” • Working documents editable by PT/EC • Published documents read-only (maintained by HMMG, strict consistency rules – tagged for development processes)

14. Questions? cover of New Yorker; August 4, 1986