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