ncBrowse: OPeNDAP Server Access and 3D Graphics

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ncBrowse OPeNDAP Server Access and 3-D Graphics

• Donald W. Denbo1 and John R. Osborne21UW/JISAO-NO
  AA/PMEL2OceanAtlas Software

http//www.epic.noaa.gov/java/ncBrowse
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Introduction

• ncBrowse is a general purpose, interactive tool
  for graphical browsing of data and attributes in
  netCDF files.
• ncBrowse can currently access OPeNDAP datasets
  that are compatible with the Java-netCDF API.
• Providing access to OPeNDAP datasets with more
  complex data models than netCDF supports, while
  challenging, is currently in development.
• ncBrowse has been significantly enhanced by
  providing 3-D visulaizations using the VisAD
  library.

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OPeNDAP - Overview

• OPeNDAP (previously DODS) is a software framework
  and protocol for providing and accessing
  scientific data over the internet.
• Client software most frequently use the netCDF
  API interface to OPeNDAP, thus minimizing the
  software modifications necessary.
• The netCDF API cannot directly and/or
  transparently access more sophisticated OPeNDAP
  data types such as Structure and Sequence.

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OPeNDAP - Goals

• Provide ncBrowse users access to the growing
  collection of datasets available via OPeNDAP.
• Access the dataset descriptor (DDS) and data
  attribute (DAS) structures.
• Combine the DAS and DDS to provide easy access to
  variables and their metadata.
• Provide an easy-to-use interface to the OPeNDAP
  Sequence and Structure objects.

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OPeNDAP data structures
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OPeNDAP - Design
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OPeNDAP - ExampleConnection to CHRIS - wind
stress
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OPeNDAP - ExampleWaiting for DAS and DDS to
download.
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OPeNDAP - ExampleCHRIS datasets data structure.
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OPeNDAP - ExampleAttributes for variable T.
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OPeNDAP - ExampleAttributes for variable absuu.
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OPeNDAP - ExampleData from variable absuu.
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OPeNDAP - ExampleWind Stress from NOAAs Buoys
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OPeNDAP - Examplenmfsws data structure.
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OPeNDAP - ExampleAttribute for variable taux.
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OPeNDAP - ExampleData from variable taux.
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3D-Visualization - Overview

• 3D visualizations are necessary to adequately
  browse certain classes of data. These include
• Float trajectories that are inherently
  3-dimensional. For example, the track of a sea
  lion or the path of an Argo float.
• Fully 3-dimensional flow fields. For example,
  turbulence and convection.
• VisAD, a Java 3D visualization package available
  from Bill Hibbard at the University of Wisconsin,
  was used.

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3D-Visualization - Goals

• 3D visualizations to include
• 3D float trajectories, colored by the value of a
  variable along the trajectory.
• 3D surfaces, colored by the value of a variable
  on the surface.
• 3D vector plots.
• Combining individual 3D visualizations into more
  sophisticated visualizations. For example,
  combining bathymetry, temperature iso-surface and
  sea lion track.

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3D-Visualization - Design

• Primary design goal is to keep the ncBrowse
  interface simple and intuitive.
• Java classes were created to wrap the VisAD
  display classes. These new classes were designed
  in interact well with ncBrowse and the Scientific
  Graphics Toolkit (SGT).
• Wrapping enables SGT applications to have easier
  access to VisAD 3D visualizations.

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3D-Visualization - Examples
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Future Directions

• OPeNDAP
• Continue development of OPeNDAP data access for
  ncBrowse.
• Recognize metadata conventions typically used in
  the WOCE and JGOFS data files.
• 3D visualizations
• Placing several 3D objects in a single display.
  For example, bathymetry, temperature surface, and
  float trajectory.
• Support VRML output.

http//www.epic.noaa.gov/java/ncBrowse