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Overview
- About the Marine Geoscience Data System
- Digital Data Repository
- Expedition Metadata Catalog
- MGDS Data Model Description
- Global Multi-Resolution Topography Synthesis
- Data Submission
- Data Access Tools
- Web Services and Interoperabilitiy
- Advisory Committee
- The MGDS Team
About the Marine Geoscience Data System
The Marine Geoscience Data System (MGDS), operated as part of the IEDA Data Facility, provides access to data portals for the NSF-supported Ridge 2000 and MARGINS, and GeoPRISMS programs, the Antarctic and Southern Ocean Data Synthesis, and the Academic Seismic Portal. These portals provide free public access to a wide variety of marine geoscience data collected throughout the global ocean. System components include a searchable digital data repository and metadata catalog, and the Global Multi-Resolution Topography (GMRT) synthesis, a dynamic multi-resolution gridded compilation of seafloor bathymetry data integrated with land topography. Data access services include keyword and map based search tools, and a Java™ based data visualization tool GeoMapApp for desktop computers and EarthObserver for iPads and other mobile devices. Open Geospatial Consortium (OGC) compliant Web Services are provided to enable access by other data systems and visualization tools. Development of the integrated data system has been underway since 2003 and has involved collaboration with researchers at WHOI, UTIG, the National Geophysical Data Center, SIO, and TAMU.
Digital Data Repository
Data hosted through the MGDS are diverse and multi-disciplinary, reflecting the multi-disciplinary nature of the science programs supported. For Ridge 2000, MARGINS and GeoPRISMS programs, the diverse data types hosted range from temperature probe data, geochemical observations, biological species compilations, MAPR and CTD data, to sidescan and sonar, photographic transects and ultra-high resolution bathymetry data. Derived data products are also served including microseismicity catalogs, images and visualization scenes, magnetic and gravity compilations, and grids of seismic layer thickness. Other derived data sets such as velocity models, tomography solutions, GIS project files and 3D visualizations are also available. For the Antarctic and Southern Ocean Data Portal and Seismic Reflection Field Data Portal, multibeam bathymetry sonar, multi-channel seismic reflection, and underway geophysical data from the R/V Palmer, R/V Gould, and the LDEO-operated research vessels the M. Ewing, and M.G. Langseth are served. As of November 2006, the data system provides free open access via the web to ~4.5TeraBytes of data, corresponding to over 196,000 digital data objects, and associated with over 1400 cruises dating back to the 1970’s.
Expedition Metadata Catalog
The backbone of the data system is a metadata catalog that serves basic expedition information, sample inventories, field and derived data. The catalog is designed to enable scientists to discover what data were collected, by who, where, and when, with links to download data if available within our local or other remote repositories. The catalog documents the existence of data sets even if not yet accessible through any digital repository. We use an open source relational database server, PostgreSQL®, and a metadata schema based on the NASA Directory Interchange Format (DIF), extended to accommodate the more complex structure of marine geoscience data. To view a more detailed description of our Data Model, click here.
Global Multi-Resolution Topography Synthesis
The primary derived data product developed and maintained by the MGDS is the Global Multi-Resolution Topography (GMRT), a dynamic global synthesis of ocean bathymetry derived from publicly available multibeam bathymetry data. The synthesis is maintained as a multi-resolution gridded global Digital Elevation Model (DEM) to ~100 m spatial resolution and is merged with land topography data from the NASA Shuttle Radar Topography Mission (SRTM). For oceanic areas, multibeam bathymetry data are merged with regional lower resolution compilations including the predicted topography of Smith and Sandwell, 1997, the International Bathymetric Chart of the Arctic Ocean, and the BEDMAP Antarctic under sea ice topography. Multibeam bathymetry data are unique among the marine geophysical data types in their relevance for a broad range of scientific investigations and non-academic uses, providing fundamental characterization of the physical environment and serving as primary base maps for multidisciplinary programs. At present, specialist expertise is needed to access and manipulate multibeam bathymetry data, which is typically available only as individual survey areas. The only other existing global compilations of seafloor bathymetry (e.g. GEBCO, Smith and Sandwell, 1997) do not include multibeam sonar data at their full spatial resolution. The MGDS provides synthesis of expedition based multibeam datasets at their full spatial resolution data for non-specialist use by maintaining a continually updated dynamic gridded global compilation. The GMRT can be accessed through GeoMapApp, Create Maps and Grids, and via Web Map Service.
Data Submission
Digital metadata forms and guidelines are provided for documenting data acquisition and sampling activities. All investigators funded by MARGINS and Ridge2000 are required to submit complete expedition documentation and field data to the MGDS within time frames set by program data policies. The MGDS team works with scientists to ensure adequate expedition documentation and basic quality assurance of data provided. All data contributed to the data system are incorporated with access restrictions until explicit permission for data release is provided by the investigator, normally under the timetable specified in published NSF data sharing requirements (see article 36) and program data policies.
Data Access Tools
Keyword search functionality provides access to the Metadata catalog and Digital Data Repository via a simple text-based search page using keywords (e.g. PI, cruise name, dates, or ship) or geographic bounds. The design of the search page facilitates easy retrieval of expedition information, field data and derived data sets. Cruises and data sets are linked to both NSF project awards as well as published references as they become available.
GeoMapApp is the primary data visualization tool integrated with the MGDS. GeoMapApp is a Java™ application, which permits dynamic exploration of data from a map interface and the capability to generate custom grids and maps (color, contour, shading, sun illumination). The application is fully integrated with the GMRT, our multi-resolution global DEM, and provides the capability to zoom and pan on the seamless land/oceanic topography database. A variety of other global data sets can be accessed and displayed including gravity, magnetics and single channel seismic profiles, seafloor age compilations, earthquake locations and seafloor bedrock geochemistry from PetDB. Options are also available for users to import their own data tables and grids and make custom maps using GeoMapApp tools. Access to all these data types is available through the same map browser as the digital elevation data, which allows the user to explore diverse global data sets and generate custom maps from a single interface.
With Create Maps and Grids a user can specify geographic bounds to generate a custom map and grid from the GMRT. Options are provided to download grids at several resolutions both with and without low-resolution regional data in areas lacking multibeam bathymetry coverage.
Web Services and Interoperabilitiy
MGDS is working to make map imagery and underlying data sets available via OGC-compliant web services. Maps created from the GMRT are available as an OGC Web Map Service(WMS) and can be accessed by any OGC-enabled client. An OGC-compliant Web Feature Service (WFS) and Web Coverage Service (WCS) are also under development, and provide direct access to underlying vector and raster data.
MGDS is working with research partners to develop metadata profiles and best practices for marine geoscience data. By applying community vocabularies and emerging earth science ontologies to existing national (FGDC) and international (ISO) standards, data from field expeditions and laboratory studies can be documented and shared. An OAI-PMH Provider/Harvester currently serves metadata records for multibeam surveys that conform to the NOAA Metadata Manager and Repository (NMMR) schema.
MGDS is working to develop data interoperability and direct links to national repositories including NGDC, IRIS, UNAVCO, and research institutions including WHOI, SIO, UTIG, TAMU, and UW. Our entire suite of collections and vocabularies is available via getCollection/getVocabulary REST-type services.
Advisory Committee
An Advisory Committee was established in 2004 to meet annually and review progress of the project components of the Marine Geoscience Data System and its partner the Geoinformatics for Geochemistry Program. A New Governance Structure was established in 2011 with the creation of the Integrated Earth Data Applications Data Facility, including both a Policy Committee and a User Committee.
The MGDS Team
The technical team for the MGDS includes Robert Arko, Suzanne O’Hara, Juliet Bonczkowski, Andrew Goodwillie, John Morton, Joyce Alsop, Rose Anne Weissel, Justin Coplan, and Samantha Chan (LDEO). Science support is provided by Suzanne Carbotte, William B.F. Ryan, and Vicki Ferrini (LDEO), along with Tom Shipley (UTIG). Graphic design for web pages by Zlata Andorova. William Haxby, who passed away in January 2006, was an original team member and the creator of GeoMapApp.
The MGDS is developed and hosted at Lamont-Doherty Earth Observatory of Columbia University, and is funded by the National Science Foundation.