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

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

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.’

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

Wow, these sound perfect…

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)

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

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

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, …

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

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

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

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

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

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

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

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

To Learn More… Attend the OPeNDAP Developer’s Meeting: Boulder, CO 21-23 Feb. Visit opendap.org Join opendap-tech@unidata.ucar.edu Participate at wiki.opendap.org

Thank You!