Input Types : MatrixType
Output Types : ImageMap
Date : 9 January 2001
The mapping makes use of 256 colors that run through the normal spectrum
from pure red to pure blue. The colors are fully saturated and of medium
intensity. The map associates red with smaller values and blue with larger
values from the input matrix.
In the first line the user can insert the value in the input matrix that will be mapped to the lowest color, red. All values below this will not be mapped to a color in the spectrum. The first selection box at the bottom of the window governs what happens: if it is ticked then they are mapped to black. If it is un-selected, they are mapped to white. If the user leaves this value at "(auto)", then the unit will map the lowest value found in the matrix to red.
In the second line the user can insert the value of the input matrix that will be mapped to the middle color, green. All values between this and the value in the first line will be interpolated to colors between pure red and pure green. By choosing this value, the user can choose to emphasize the upper or lower range of values by giving them more color range. The interpolation is linear, unless the third selection box at the bottom of the window is set to logarithmic. Then the interpolation is linear in the logarithm, as in logarithmic axes on a graph. If the user leaves the second line at "(auto)", then the value midway (linearly or linear-logarithmically) between the values in the first and third lines will be mapped to green.
In the third line the user can insert the value of the input matrix that will be mapped to the highest color, blue. All values above this will not be mapped to a color in the spectrum. The second selection box at the botrtom of the window governs what happens: if it is ticked then they are mapped to white. If it is un-selected, they are mapped to black. If the user leaves this value at "(auto)". then the unit will map the highest value found in the matrix to blue.