Directory name: contrib/PRAVDA/programs
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The user has a choice between a direct image display or a rendered image. Two of the data sets are on curvilinear grids (airfoil and jet engine noise). Hence, the results with a direct image will not be correct. Two of the data sets are on a regular grid but not with square "pixels" (ozone pollution and auroral image). Hence, the direct image will appear to be stretched. Three of the data sets have regions which are invalid (global ozone, 100mb global wind and auroral image).
As part of the caption, the surface area of the isosurface is displayed. The surface area is calculated using the Measure module.
In this visual program, the gradient of the electron density field is mapped onto an isosurface of the field. The result is colored with a colormap appropriate for these data.
This example visual program shows you a few ways to use color maps. First choose "Open All Control Panels" from the Windows menu. A selector interactor allows you to experiment with four different kinds of color mapping as offered by PRAVDAColor -- isomorphic or continuous, segmented, highlighting, and the default (hue-based rainbow as offered by AutoColor). In each case, a Colormap Picker panel pops up that allows you to select a type of colormap and modify its range. Further modifications of these colormaps may be done within the Colormap Editor (hit Ctrl-E in the Image Window).
In order to have abrupt boundaries between colors in the second (segmented) choice, the data to be mapped must be dependent on the "connections" (in this case triangles) rather than "positions". This will result in the colors also being dependent on the connections, and every triangle will have a constant color. We use the Post module to change the data dependency from "positions" to "connections".
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