ncBrowse: OPeNDAP Server Access and 3-D Graphics
Presented byNancy N. Soreide
NOAA/PMEL
http://www.epic.noaa.gov/java/ncBrowse
Donald W. DenboUW/JISAO-NOAA/PMEL
John R. Osborne OceanAtlas Software
2003-06-05 NOAAResearch WebShop 2003, Longmont, CO 2
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.
Display of OPeNDAP data and attribute structures
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OPeNDAP - Design
netcdf2
http/1.1 OPeNDAP
NcBrowsedata file browser
OPeNDAPServer
WebServer
netcdffile
netcdffile
OPeNDAPfile {Netcdf
hdfJGOFS
OPeNDAPdataset
list
{ dasddsinfo
OPeNDAP Connection to “CHRIS” - wind stress from LDEONotice that the format of the data file is not important
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.
Setting up a 3D-Visualization with ncBrowse
X=temperature
Y=pressure
Z=salinity
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