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.