Specialized Color Function for Display of Signed Data
- Created: Monday, 01 December 2008
This Mathematica script defines a color function to be used with Mathematica’s plotting modules for differentiating data attaining both positive and negative values. Positive values are shown as shades of blue, and negative values are shown in red. The intensity of the color reflects the absolute value of the data value.
The quantization is the same for both positive and negative values, so that comparable intensities accurately reflect comparable data magnitudes. Customization is done through several software switches. The number of color bins to be used is selected by “nshades.” “Linear” is set to 1 for a linear mapping of data magnitudes to color, and set to 0 for nonlinear mapping. The nonlinear choice uses a cube root data-mapping to encompass a large data range while accentuating the smaller data values. This innovation allows nonlinear stretching of data to enhance visualization at the low end of the scale while still viewing the entire data range (the data range set by the user).
This work was done by Virginia Kalb of Goddard Space Flight Center. For further information, contact the Goddard Innovative Partnerships Office at (301) 286-5810. GSC-15128-1