NetCDF Dataset, NcML, OGC, Common Data Model Slides

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NetCDF Dataset, NcML, OGC, Common Data Model
Slides

• November 2004

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Data Catalog and Dataset Discovery and
AccessScenario
Discovery Center Search Service
Step 1
Data User with Browser and/or Desktop Data
Analysis Application
Data search or browse query
Pointers to inventory and enhanced catalogs
Request for inventory catalog
Request for enhanced catalog
Inventory catalog list
Step 2
Step 2
Enhanced catalog
Request for dataset
Dataset
Third Party Enhanced Catalog Service
Data Center Inventory Catalog Service
Step 3
Data Center Data Service
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Catalogs

• XML files containing
• descriptive information about datasets
• lists of pointers to metadata about
• dataset collections
• individual datasets
• individual files
• metadata in NcML dialect

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NcML represents

• Metadata internal to netCDF files
• Additional descriptive metadata for datasets and
  files
• Coordinate system of datasets
• Specification of
• subset of data in netCDF file(s), e.g., only
  certain parameters or only certain observing
  stations in point data files
• aggregation of data in multiple netCDF files,
  e.g., time series of data files
• subset of data in multiple files, e.g., time
  series of data from specific observing stations

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Presently Supported Client/Server Facilities
Application
THREDDS
HTTP
Catalog.xml
NetCDF-3
IOsp

GRIB
NIDS
GINI


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OGC Data Service Protocols
Application
WFS
WCS
GML
DTED
GeoTIFF
Static GIS Features
NITF
HDF-EOS

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OGC Data Service with NetCDF Dataset Protocols
Application
WFS
WCS
GML
DTED
Static GIS Features
NITF
HDF-EOS

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OGC Data Service with NetCDF Dataset Protocols
Application
WFS
WCS
NetcdfDataset
GML
DTED
GeoTIFF
Static GIS Features
NITF
HDF-EOS
ADDE
OpenDAP
netCDF file

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Common Data ModelTransport/Access Mechanisms

• Provides common application programming interface
  layer
• Enables access via client/server protocols
• HTTP
• OPeNDAP
• ADDE
• Direct file open/read from local disk

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Common Data ModelData Storage Formats

• Provides common application programming interface
  layer
• Enables access to data storage formats
• Time-varying point data (e.g., weather or stream
  flow station measurements)
• 5D gridded data (e.g., output of forecast models)
• Image Data (e.g. satellite observations)
• Special data forms (may be special cases of those
  above)
• Sounding profiles (balloons, aircraft, ocean
  CTDs)
• Conic sweeps (ground based radars
• Swath images (satellite-borne radars, bathymetry)

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Application
NetCDF-Java version 2.2
NetcdfDataset
NetcdfFile
HTTP
HDF5
NetCDF-3
IOsp
NetCDF-4
GRIB
NIDS
GINI



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Application
NetCDF-Java version 2.2 (Johns)
NetcdfDataset
NetcdfFile
ADDE
OpenDAP
THREDDS
HTTP
HDF5
NetCDF-3
IOsp
Catalog.xml
NetCDF-4
GRIB
GINI
(Johns original diagram)
NIDS

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