ncBrowse: OPeNDAP Server Access and 3-D Graphics

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ncBrowse OPeNDAP Server Access and 3-D Graphics
Donald W. DenboUW/JISAO-NOAA/PMEL
John R. Osborne OceanAtlas Software

• Presented byNancy N. SoreideNOAA/PMEL

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

• ncBrowse is a Java Application initially designed
  to graphically browse netCDF files.
• Flexible, interactive graphical displays of data
• Tree and table views of netCDF file schema
• Publication quality printable graphics with
  science features such as contour plots,
  self-scaling time axes, etc.
• Supports a wide range of netCDF conventions
• COARDS oceanic/atmospheric data sets (gridded)
• EPIC oceanic observations, profile and time
  series
• Available for Windows, Unix, MAC OS
• Popular!
• ncBrowse has been downloaded over 8476 times to
  3528 unique sites in 59 countries.

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ncBrowse Overview
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ncBrowse, OPeNDAP and 3D graphics

• 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 uses 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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Display of OPeNDAP data and attribute structures
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OPeNDAP - Design
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OPeNDAP Connection to CHRIS - wind stress from
LDEONotice that the format of the data file is
not important
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Connection to Wind Stress from NOAAs Buoys from
URIOPeNDAP structure reveals data is a JGOFS
sequence
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3D-Visualization - Overview

• 3D visualizations are necessary to adequately
  browse certain classes of data. E.g.,
• Float trajectories are inherently 3-dimensional.
  E.g., track of a sea lion or path of an Argo
  float.
• Fully 3-dimensional flow fields e.g., turbulence
  and convection
• Utilized VisAD, a Java 3D visualization package
  from Bill Hibbard at the University of Wisconsin.

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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

• User interface
• Primary design goal is to keep the ncBrowse
  interface simple and intuitive.
• Technology
• 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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Setting up a 3D-Visualization with ncBrowse
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Xtemperature Ypressure Zsalinity Colored by O2
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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