This directory contains example programs using PRAVDA (Perceptual Rule- based Architecture for Visualizing Data Accurately), which is designed for use with the IBM Visualization Data Explorer. These programs and tools require DX Version 3.1 or later.
The primary tool is called PRAVDAColor. It does invoke other modules and and macros. You can use PRAVDAColor as you would currently use the AutoColor or AutoGrayScale or Colormap and Color modules. PRAVDAColor has two methods of selecting colormaps. The default is to provide a "best" colormap based upon the visualization task and the data. Alternatively, PRAVDAColor can pop up a colormap selector widget with the suggested choices for colormaps. You may adjust the ranges for the colormaps, but need to choose one. The specific colormaps are offered based upon the visualization task you selected and the spatial characteristics of the data. The available tasks are 1) isomorphic/continuous; 2) segmented; 3) highlighting or 4) default (i.e., rainbow as in AutoColor).
Documentation is provided within each example network or with associated files in these directories. Look within the comment field under control panels and visual program editor windows for this information.
You have the following subdirectories:
o Colormaps, which contains the color map library for use with PRAVDAcolor
o PRAVDAtools, which contains macros and modules used for PRAVDA including PRAVDAcolor
o data, which contains some simple static data sets for use with the examples.
o programs, which contains seven example programs that use PRAVDAColor
PRAVDAexample
This program allows the user to choose among twelve different two-dimensional static data sets to examine as a pseudo-color image. According to the visualization task, which is also selected by the user, and the characteristics of the data, PRAVDAColor offers a choice of one or more appropriate color maps to be applied to the data. PRAVDAColor uses perceptual rules to identify appropriate color maps from a provided library.
ThunderGlyphSheet
This program is a modification of one of the DX sample programs in /usr/lpp/dx/samples/programs, in which an instance of AutoColor is replaced with PRAVDAColor. The data are a simulation of a severe thunderstorm. An isosurface shows cloudwater density, a colored plane shows temperature (and is in addition deformed by an amount proportional to the temperature), while red glyphs show the wind velocity near the base of the storm. PRAVDAColor is used to color the deformed plane.
Choose Open All Control Panels from the Windows menu. You can then control the isosurface value, the opacity of the isosurface, the vertical position of the plane showing temperature, and the magnitude of deformation of the plane, and the type of visualization task to select the color map for the deformed plane.
example1, example2, example3, example4, UsePRAVDAColor and UsePRAVDAColor2 are very simple networks to show how PRAVDAColor can be used in standard DX applications in progressively more complex fashions.
In addition, there is a short c-shell script, PRAVDA_demo, which can be used to start up dx and allow you to try these example programs. Another csh script, PRAVDA_editor sets up PRAVDAColor for use in developing new networks.
For more information about PRAVDAColor, read
L. D. Bergman, B. E. Rogowitz and L. A. Treinish. "A Rule-based Tool for Assisting Colormap Selections". Proceedings of the IEEE Computer Society Visualization '95 Conference, pp. 118-125, October 1995.
and
B. E. Rogowitz and L. A. Treinish. "How NOT to Lie with Visualization". Computers in Physics, 10, n.3, May/June 1996.
If there are questions, problems or suggestions associated with this material, contact:
Lloyd Treinish IBM T. J. Watson Research Center P. O. Box 704 Yorktown Heights, NY 10598 lloydt@watson.ibm.com (internet) 914-784-5038 (voice) 914-784-5130 (facsimile)
Directory name: contrib/PRAVDA
Other files in this directory:
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