1. Reference Architecture and Agile Development Presentation to NASA Standards Process Group Reference Architecture workshop at the ESIP Federation Meeting George Percivall OGC Chief Architect 22 July 2010 Copyright © 2010, Open Geospatial Consortium, Inc.

2. Making Location Count… Reference Architecture and Agile Development Architecting Reference Architectures Agile Development Some examples Copyright © 2010, Open Geospatial Consortium, Inc.

3. Making Location Count… Architecture and Architecting Architecture –Organization of a system embodied in its components, their relationships to each other and to the environment and principles guiding its design and evolution (IEEE P1471) Architecting Approaches –Heuristics:Rule of thumb –Stakeholders: Process –Normative:Standards Systems Architecting, Eberhardt Rechtin, Prentice Hall, 1991 Copyright © 2010, Open Geospatial Consortium, Inc.

4. Making Location Count… © 2006, Open Geospatial Consortium, Inc.4 Architecting Heuristics The greatest leverage in system architecting is at the interfaces - Eberhard Rechtin Look for misfits with context and design to minimize them - Christopher Alexander Running code wins - IETF Solutions should be as simple as possible, but no simpler – Albert Einstein Simple ain’t easy – Thelonious Monk

5. Making Location Count… Reference Architecture Standards IEEE 1471 –General process. Requires viewpoints but does not define any. RM-ODP –Reference Model for Open Distributed Processing –Enterprise, Informational, Computational, Engineering, Technology –Viewpoint languages coordination with UML OASIS Reference Model for Service Oriented Architecture –Focused on Services Others: DODAF, TOGAF, Zachman Copyright © 2010, Open Geospatial Consortium, Inc.

6. Making Location Count… SUMMARY OF ARCHITECTURE STANDARDS Source: GST Interoperability Group, 2002

7. Making Location Count… SUMMARY OF ARCHITECTURE STANDARDS Maintenance organization – what organization is responsible for establishing, updating and distributing the standard. Architecting products defined? – Does the standard define what items, e.g., views, shall be used to define an architecture? Architecting process defined? – Does the standard define the steps that an organization shall perform in order to develop an architecture? Standards Category Model? – Does the standard provide an outline for organizing standards that shall be used to define architectures. (These categories are the basis for a Standards Technical Reference Model) Required standards listed? – Does the standard provide specific standards that shall be used to be compliant to the architecture standard? Standards Development Process? – Does the standard define a process for developing or adopting standards? The Zachman Framework is not included in the evaluation as it is a proprietary approach not allowing for comparison. Copyright © 2010, Open Geospatial Consortium, Inc.

8. Making Location Count… RM-ODP Viewpoints – Separation of Concerns “GIGAS Methodology for comparative analysis of information and data management systems” OGC Best Practice, 10 ‑ 028r1

9. Making Location Count… Examples of Reference Architecture for Evolutionary Development OGC Reference Model (ORM) –Overview of OGC Standards Baseline –Resource for defining architectures for specific applications GEOSS Architecture Implementation Pilot –System of Systems based on Interoperability Arrangements –Process of iterative development while refining an architecture –AIP Architecture using RM-ODP http://www.ogcnetwork.net/AIpilot Copyright © 2010, Open Geospatial Consortium, Inc.

10. GEOSS AIP Enterprise Viewpoint

11. GEOSS AIP Information Viewpoint Source: GEOSS AIP-3 Architecture – Information Viewpoint

12. GEOSS Clearinghouses GEO Web Portals GEOSS Common Infrastructure Components & Services Standards and Interoperability Best Practices Wiki User Requirements Registries Main GEO Web Site CSWWMS CSW Registered Community Resources Community Portals Client Applications Client Tier Business Process Tier Community Catalogues Alert Servers Workflow Management Processing Servers Access Tier GEONETCast Product Access Servers Sensor Web Servers Model Access Servers Test Facility Mediation Servers CSWWMSCSWW*S WMSWFS SOSSASSPSW*S CSW WPS Engineering Viewpoint

13. OGC 13 ISO 19101-2 – Geographic Information – Reference Model – Imagery Engineering viewpoint - Nodes

14. Making Location Count… Prototyping Versus Specifying “Prototyping Versus Specifying: A Multiproject Experiment” 1) Prototyping yielded products with roughly equivalent performance, but with about 40 percent less code and 45 percent less effort. 2) The prototyped products rated some what lower on functionality and robustness, but higher on ease of use and ease of learning. 3) Specifying produce produced more coherent designs and software that was easier to integrate. –BARRY W. BOEHM, TERENCE E. GRAY, AND THOMAS SEEWALDT, IEEE TRANSACTIONS ON SOFTWARE ENGINEERING, VOL. SE-10,NO. 3,MAY 1984 See also Michael Schrage, e.g., Serious Play and “Cultures of Prototyping” in Bringing Design to Software Copyright © 2010, Open Geospatial Consortium, Inc.

15. Making Location Count… Agility and Architecture Use agile development to get to a good architecture by appropriately applying suitable combinations of –architectural functions (such as communication, quality attributes, and design patterns) and –architectural skills at four points in the development life cycle. (up-front planning, storyboarding, sprint, and working software) http://www.computer.org/cms/Computer.org/ComputingNo w/homepage/2010/0410/T_SW_AgileArchitectureInteractio ns.pdf Copyright © 2010, Open Geospatial Consortium, Inc.

16. Making Location Count… IEEE SOFTWARE - March/April 2010

17. GEO AIP Evolutionary Development Process DevelopmentActivities Kick-offWorkshop Call for Participation ConceptDevelopment PersistentOperations(AR-07-01) Participation ArchitectureDocumentation Updates for each step Baseline AR-07-02 Architecture Implementation Pilot Evolutionary Development Process Operational Baseline and Lessons Learned for next evolutionary spiral Continuous interaction with external activities

18. 4. Deployment Plan 4. Deployment Plan 1. SBA Scenarios 1. SBA Scenarios 2. Enterprise Models 2. Enterprise Models 3. Engineering Design 3. Engineering Design Component Types Information Framework Optimize Specify AIP: Using the Architecture Views in the Evolutionary Development Process Use Cases Services

19. Making Location Count… David Byrne: How Architecture helped music evolve http://www.ted.com/talks/david_byrne_how_architecture_helped_music_evolve.html He asks: Does the venue make the music? –From outdoor drumming to Wagnerian operas to arena rock, Byrne explores how context has pushed musical innovation. Model for creation (at 13:45 in talk) –We make music primarily in a form to fit the context and we make art to fit museum walls –We write software to fit existing operating systems. Its evolutionary, its adaptive. –This is a reverse view from the traditional romantic view: first comes the outpouring of emotion and then somehow it gets shaped into something. –The passion is still there, but the vessel that it is going to be injected into and poured in to is instinctively and intuitively created first. Copyright © 2010, Open Geospatial Consortium, Inc.

20. Making Location Count… For Details on OGC Standards… OGC Standards –Freely available – www.opengeospatial.org/standards www.opengeospatial.org/standards OGC Reference Model (ORM) –Overview of OGC Standards Baseline –Resource for defining architectures for specific applications – www.opengeospatial.org/standards/orm www.opengeospatial.org/standards/orm George Percivall, gpercivall at opengeospatial.orggpercivall at opengeospatial.org Copyright © 2010, Open Geospatial Consortium, Inc.