CEOS WGISS 20, Kyev, September 12-16, 2005
Introduction and OverviewOf GALEON IE
September 12, 2005
Osamu Ochiai - JAXA
Ben Burford - JAXA/RESTEC
CEOS WGISS 20, Kyev, September 12-16, 2005
GALEON IE(Geo-interface for Air, Land,
Earth, Oceans NetCDF)Interoperability Experiment
Ben Domenico/UCARGeorge Percivall/OGC
Support open access to atmospheric and oceanographic data.
CEOS WGISS 20, Kyev, September 12-16, 2005
Main Gateway Objectives
• Investigate the feasibility of adapting data and metadata originating from OPeNDAP and THREDDS servers to the WCS specifications– To bridge the gap between the climate research
and GIS communities
• Allow traditional GIS clients to access netCDF/OPeNDAP datasets via standards-based interface – “WCS-THREDDS Gateway”
CEOS WGISS 20, Kyev, September 12-16, 2005
NetCDF/OPeNDAP NetCDF/OPeNDAP data serverdata server
WCS Client
…
THREDDS THREDDS catalogs catalogs
enhanced with enhanced with NcML-GMLNcML-GML
WCS capabilities
THREDDS interface
WCS description
THREDDS interface
OPeNDAP
NetCDF dataset
NetCDF
OPeNDAP
GMLgenerator
geoTIFFgenerator
WCS coverage
netCDFgeoTIFF
NcMLGMLgetCoverage
getCapabilities
describeCoverage
THREDDS enhanced catalog generation tools
THREDDS catalogsNcML-G metadata
netCDF objects
CEOS WGISS 20, Kyev, September 12-16, 2005
NcML-GML ver. 0.5
• A Mediation Markup Language between ncML and GML
• An extension of ncML (netCDF Markup Language) based on GML grammar
• Why? – Because NcML (i.e. netCDF) and GML semantics are not completely interoperable
• To keep ncML and GML loosely coupled– NcML must be free to change without any direct effect
on GML, and vice versa.• WCS-THREDDS server
– Gateway between UNIDATA THREDDS and OGC-WCS
CEOS WGISS 20, Kyev, September 12-16, 2005
AS and GIS domains
• Historical differences:
Focus on geo-location
Low (low resolution, intrinsic inaccuracy)
High (spatial queries support, high resolution)
Focus on temporal evolution
High (Temporal series support, high variance: seconds to centuries)
Low (low variance)
Data types Multi-dimensional arrays (at least 3-D + time)
Topological features (usually 2-D geometry) referred to a geo-datum
– special case: Coverage
GIS AS
CEOS WGISS 20, Kyev, September 12-16, 2005
netCDF + Conventions
Interoperability issue
Encoding level
Abstract model level
Multi-dimensionalarrays
Coverage
netCDF encodings GML
AS GIS
Content model level
OGC/ISO Coveragemetadata
CEOS WGISS 20, Kyev, September 12-16, 2005
Model mediation approach
ISO 191xxModel
netCDFData Model
THREDDSData Model
ncML-GData Model
GML 3.xData Model
GML 3.xData Model
Models Mediation
GIS (Geospatial)InformationCommunity
Earth SciencesInformationCommunity
• To experiment effective solutions to mediate AS and GIS data models
ncML-GML
Data Model
ncML-GML
Data ModelWCS 1.x
Data ModelWCS 1.x
Data Model
CEOS WGISS 20, Kyev, September 12-16, 2005
Interoperability Experiment
Encoding level
Abstract model level
AS GIS
Content model level
ncML-GML abstract model
ncML-GML content model
ncML-GMLGGMLMLGGMLML
CEOS WGISS 20, Kyev, September 12-16, 2005
Participants• Unidata/UCAR* (Ben Domenico)• University of Florence*• NASA Geospatial Interoperability Office*• George Mason University (Liping Di)• CadCorp• ESRI• JPL• IMAA-CNR• Interactive Instruments• University of Applied Sciences• International University Bremen• NERC NCAS/British Atmospheric Data Center• University of Alabama Huntsville (Mike Botts)• Research Systems, Inc. (IDL)• Texas A&M University
*Initiating institutions
CEOS WGISS 20, Kyev, September 12-16, 2005
Non-member Interestin Gateway Implementation
• University of Rhode Island (OPeNDAP group)*• Pacific Marine Environment Laboratory (PMEL)*• Center for Land, Ocean, Atmosphere (COLA)• Marine Metadata Initiative lead by MBARI (Monterey
Bay Aquarium Research Institute)• GODAE (Global Ocean Data Assimilation Experiment)
led by FNMOC (Fleet Numerical Meteorological and Oceanographic Center)
• Many current THREDDS/OPeNDAP server sites
CEOS WGISS 20, Kyev, September 12-16, 2005
Conclusion:Main Interface Objectives
• Evaluate effectiveness of ncML-GML in WCS data encoding… suggest extensions
• Evaluate netCDF/OPeNDAP as WCS data transport (encoding) mechanism … suggest extension if warranted
• Responsibilities:– UCAR: develop the testbed– OGC: evaluate and update the specifications.