Status Report: April 2013 - Oct 2013

John Caron, Ethan Davis, Dennis Heimbigner, Sean Arms, and Lansing Madry

Strategic Focus Areas

The THREDDS group's work supports the following Unidata funding proposal focus areas:

  1. Enable widespread, efficient access to geoscience data

    The work of the THREDDS group is comprised of two main areas: the THREDDS Data Server (TDS) and the Common Data Model (CDM) / netCDF-Java library. The TDS provides catalog and data access services for scientific data using OPeNDAP, OGC WCS and WMS, HTTP, and other remote data access protocols. The CDM provides data access through the netCDF-Java API to a variety of data formats (e.g., netCDF, HDF, GRIB). Layered above the basic data access, the CDM uses the metadata contained in datasets to provide a higher-level interface to geoscience specific features of datasets, in particular, providing geolocation and data subsetting in coordinate space. The CDM also provides the foundations for all the services made available through the TDS.

    The data available from the IDD is a driving force on both the TDS and netCDF-Java development. The ability to read all the IDD data through the netCDF-Java library allows the TDS to serve that data and provide services on/for that data.

  2. Develop and provide open-source tools for effective use of geoscience data

    Unidata's Integrated Data Viewer (IDV) depends on the netCDF-java library for access to local data, and on the THREDDS Data Server (TDS) for remote access to IDD data. At the same time, the CDM depends on the IDV to validate and test CDM software. Many other tools build on the CDM / netCDF-Java library (eg ERDDAP, Panolpy, VERDI, etc) and on the TDS (LAS, ncWMS, MyOcean, etc).

  3. Provide cyberinfrastructure leadership in data discovery, access, and use

    The Common Data Model (CDM) / netCDF-Java library is one of the few general-purpose implementations of the CF (Climate and Forcast) metadata standards. Current active efforts in CF that we are involved with include draft Satellite and Radar Conventions.

    The TDS has pioneered the integration of Open Geospatial Consortium (OGC) protocols into the earth science communities. Strong international collaborations have resulted in WCS and WMS services as part of the TDS.

    The CDM and TDS are widely used implementations of the OPeNDAP DAP2 data access protocol. Unidata is working with the OPeNDAP group to design, develop, and implement a new version of the DAP specification, DAP4.

Activities Since the Last Status Report

Release Status of CDM and TDS

  • CDM and TDS 4.3.18 are the current stable releases.
  • Unidata TDS: The switch to TDS 4.3 (and the new GRIB handling code, including new GRIB variable names) has been made on all Unidata managed TDS installations.

Collaboration Activities

  • Three EarthCube Building Blocks Proposals funded:
  • Work continues on OPULS (OPeNDAP-Unidata Linked Servers) project to finalize DAP4 specification, implement DAP4 clients and servers, develop DAP4 conformance testing capabilities. The OPULS project recieved third year funding from NOAA -- approximately one third of originally budgeted amount.
  • Working with NOAA/ESRL/GSD on checking the GRIB tables used with HRRR and FIM data.
  • Work underway on project for "Project to Improve Software Infrastructure in Support of the NOAA National Climate Model Portal (NCMP)", funded by NOAA/NOMADS grant.
  • ncSOS plug-in developed by ASA (Applied Science Associates) and USGS CIDA provides OGC SOS service for data conforming to the CF Discrete Geometries data types. Looking at distributing with the TDS version 5.0.

International Standards Development

  • Track and participate in OGC MetOcean Working Group discussion.
  • Track and participate in OGC WCS development.
  • Track and participate in OGC CF-netCDF development.


  • Marcos Hermida accepted a position at ECMWF, his last day at Unidata was 23 September 2013. He made major contributions to the THREDDS software and development process while here. We hope to find opportunities to collaborate with him in the future.

Planned Activities

CDM/TDS 4.4 Development (underway)

We plan to continue the following activies:

  • Port Earth System Grid (ESG) requested enhancements from TDS 4.2 (see TDS-213)
  • Refactor TDS catalog caching for Earth System Grid (ESG)
  • Ugrade CDM/TDS use of HttpClient from 3.x to 4.x (3.x is end-of-life)
  • Consolidate CdmRemote service under NCSS interface (plan to do similar with RadarServer service)
  • Add WRF initialization service to NCSS
  • Add WaterML as output format from NCSS point service
  • Simplify process for adding new TDS web services. Document simplified process so third-party development groups can more easily add new web services to the TDS.
  • Work with ncWMS group and others to add features to the version of ncWMS used by TDS.
  • Experiment in TDS with various server-side processing capabilities.
  • Experiment in TDS with Asynchronous responses

CDM / TDS 4.5 Development

  • DAP4
  • Grid Feature Collection (assimilate FMRC?)
  • Add Constant Forecast Offset/Hour back to GRIB
  • CdmRemoteFeature for all CF-DSG feature types

CDM / TDS 5.0 Development

  • Catalog 2
  • TDS configuration refactor (ease of use and support dynamic re-init)
  • Refactor GridDatatype to Coverage
    • Swath/Image
    • Unstructured Grid
    • Time-dependent coordinate system
    • Cross-seam lat/lon data requests
  • Improved metadata harvesting support
  • Search/discovery service?
  • Require Java 7 and Tomcat 7 (start using java.nio.file)