ncBrowse: OPeNDAP Server Access and 3-D Graphics Presented by Nancy N. Soreide NOAA/PMEL Donald W. Denbo UW/JISAO-NOAA/PMEL John R. Osborne OceanAtlas Software

NOAAResearch WebShop 2003, Longmont, CO2 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.

NOAAResearch WebShop 2003, Longmont, CO3 ncBrowse Overview

NOAAResearch WebShop 2003, Longmont, CO4 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.VisAD library

NOAAResearch WebShop 2003, Longmont, CO5 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.

NOAAResearch WebShop 2003, Longmont, CO6 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

NOAAResearch WebShop 2003, Longmont, CO8 OPeNDAP - Design

OPeNDAP Connection to “CHRIS” - wind stress from LDEO Notice that the format of the data file is not important

Connection to Wind Stress from NOAAs Buoys from URI OPeNDAP structure reveals data is a JGOFS sequence

NOAAResearch WebShop 2003, Longmont, CO11 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.

NOAAResearch WebShop 2003, Longmont, CO12 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.

NOAAResearch WebShop 2003, Longmont, CO13 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 O 2

NOAAResearch WebShop 2003, Longmont, CO18 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.