1. Using Community-Driven Metadata Conventions with On-Line Data
James Gallagher*,
Daniel Holloway*,
Dan Lohaus**
*OPeNDAP
**Northrop-Grumman

2. Overview What are ‘Community-Driven Standards?’
How Does OPeNDAP’s new data server support them?

3. Community-Driven Standards
Origin: Solutions as opposed to descriptions of problems
Most often developed by users or developers that are also users
Once implemented, ‘convention’ promoted to a ‘standard’ after a significant number of users ‘vote with their feet.’

4. More characteristics…
Generally small and focused on a part of a problem
Good components
The ‘insides’ are comprehensible.
Flexible; easy to use in unforeseen ways

5. Wow, these sound perfect…

6. Wow, these sound perfect…
Implementations can limit growth (success creates users with an expectation of stability)
Uncontrolled proliferation is possible
Free-wheeling; lack of rigor
Many ‘Community-Driven Standards’ actually do go through a formal process
IETF and IETF-like (e.g. NASA/ESE/SPG)
Technology adopted by ISO
Test bed to voting body (IEEE, OGC)

7. Examples Relevant to Data Systems
Well known, with broad appeal: HTTP, MIME
XML: micro formats
Services: SOAP
Data standards: DAP (aka OPeNDAP), WxS
Metadata conventions: COARDS, CF, THREDDS

8. OPeNDAP’s Server4
Uses a modular architecture to support different application-level protocols
Data access using DAP
Catalogs using THREDDS
Browsing using HTML and ASCII
Modules for data access
Different file types
Potential for database and scripting
Modules for commands
Commands provide varying operations for different protocols

9. Server4 OLFS BES BES Commands DAP2 THREDDS HTML
Java
Servlet Engine
BES Commands
BES
Unix Daemon
DAP2
THREDDS
HTML
XML- encapsulated object
Optional THREDDS catalogs
File system with data files,
SQL Database, …

10. DAP2 Request/Reply Logic
OLFS
OLFS
DAP2 Request/Reply Logic
DAP2
BES Commands/
XML Documents
Java Servlet Engine

11. DAP2 Request/Reply Logic
OLFS
OLFS
DAP2 Request/Reply Logic
DAP2
BES Commands/
XML Documents
THREDDS
THREDDS R/R Logic
Java Servlet Engine

12. DAP2 Request/Reply Logic
OLFS
OLFS
DAP2 Request/Reply Logic
DAP2
BES Commands/
XML Documents
THREDDS
THREDDS R/R Logic
HTML R/R Logic
HTML
Java Servlet Engine

13. DAP2 Request/Reply Logic
OLFS
OLFS
DAP2 Request/Reply Logic
DAP2
BES Commands/
XML Documents
THREDDS
THREDDS R/R Logic
HTML R/R Logic
HTML
SOAP-DAP R/R Logic
SOAP
Java Servlet Engine

14. BES BES Framework Network Protocol and PPT* Process start/stop
activities
BES Commands/
XML Documents
Commands**
Data Store Interfaces
*PPT is built in
**Some commands are built in

15. BES BES Framework Network Protocol and Initialization/ PPT*
Termination
Network Protocol and
Process start/stop
activities
BES Commands/
XML Documents
Commands**
Data Store Interfaces
*PPT is built in
**Some commands are built in

16. BES BES Framework PPT* Initialization/ Termination
Network Protocol and
Process start/stop
activities
DAP2
Access
Data
Catalogs
BES Commands/
XML Documents
Commands**
Data Store Interfaces
*PPT is built in
**Some commands are built in

17. BES BES Framework PPT* Initialization/ Termination
Network Protocol and
Process start/stop
activities
DAP2
Access
Data
Catalogs
BES Commands/
XML Documents
Commands**
NetCDF3
HDF4
FreeForm
Data Store Interfaces …
*PPT is built in
**Some commands are built in

18. To Learn More…
Attend the OPeNDAP Developer’s Meeting: Boulder, CO Feb.
Visit opendap.org
Join
Participate at wiki.opendap.org

19. Thank You!