ncBrowse: A Graphical netCDF File Browser

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ncBrowse A Graphical netCDF File Browser

• Donald Denbo
• NOAA-PMEL/UW-JISAO

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

• ncBrowse is a Java Application designed to
  graphically browse data files in netCDF format.
• netCDF is available from Unidata and is
• Widely adopted by the oceanic and atmospheric
  communities
• Machine-independent format
• Array-oriented
• Self describing
• Available for the Java, C, C, and Fortran
  languages

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Overview

• ncBrowse provides
• Flexible, interactive graphical displays of data
• Tree and table views of netCDF file schema and
  attributes
• Supports a wide range of netCDF conventions
• COARDS oceanic/atmospheric data sets (gridded)
• EPIC oceanic observations, profile and time
  series
• Next release will provide network access to DODS
  data files
• ncBrowse has been downloaded 4749 times to 2265
  unique sites in 55 countries as of July 1, 2002.

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Features

• SGT graphics for 1 and 2 dimensional cuts through
  data
• Handles files with character variables.
• Handles dimensions without associated variables
• Properly decodes several time formats
• Access to remote data files via DODS (beta
  version).
• Direct access to remote netCDF files from the Web
  (even without DODS).
• Vector plots (beta).
• Variable mapping (beta).
• Animations by varying parameters in Variable Map
  (beta).
• Available for UNIX, Win32, and MacOS
• Graphics appearance easily modified
• Printing support

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Virtual Demo
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Virtual Demo
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Virtual Demo
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Virtual Demo
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Vector Demonstration
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Design Goals

• Easy to use.
• Graphical user interface designed to provide a
  natural navigation through netCDF file
  contents.
• Platform neutral.
• Operates on UNIX, Win32, MacOS X, and MacOS 9.x
  (v1.0 only).
• Independence from netCDF conventions.
• Does not require netCDF files to conform to a
  specific convention.
• Does recognize some conventions, if present. For
  example, EPIC and COARDS time conventions.
• Easy to compare netCDF files.
• Multiple netCDF files and graphics windows can be
  simultaneously open

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Variable Mapping

• Update data handling to support variable mapping.
• Support
• Line plots assigning any two variables or
  dimensions
• Grid plots.
• Vector plots.
• Parametric plots.
• For example, temperature vs. salinity, with depth
  the parameter.
• Flexible mapping of independent variables to
  graphical axes.
• For example, a file that contains lat, lon, and
  temp as separate netCDF variables could be mapped
  so that lat -gt y-axis, lon -gt x-axis, and temp -gt
  z-axis.

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Mapping Examples
Line Plot Where i, the depth index, varies.
Grid Plot Where i, j, the latitude and longitude
indices, vary, and k is held constant.
Vector Plot Where i, k, the x-axis and depth
indices, vary and j, m are held constant.
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Future Directions(version 1.4 and beyond)

• Color palette control
• Set range for colorbar
• Use zoomed range of graph for colorbar range
• Improved graphics capabilities.
• Contour plot control (editing color map, contour
  levels, etc.)
• Co-plotting variables
• Global and variable attribute editing.
• Modification of local netCDF files.

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Future Directions(version 1.4 and beyond)

• Allow mouse interrogation of data values.
• Logarithmic axis support.
• Full access to OPeNDAP (formerly DODS) servers.
• 3-D visualizations using VisAD.

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Availability

• NcBrowse is freely available from the ncBrowse
  web page, at http//www.epic.noaa.gov/java/ncBrows
  e and includes
• Download options for Mac, PC, and Unix (notice
  that V1.3.3Beta5 includes the Java Virtual
  Machine)
• Users E-Mail Archive (ncBrowse related
  discussions and questions)
• News and updates
• On-line help