4.1.3. Spectral Diagram
Any number of columns can be selected by clicking [Variable]. The columns may contain missing values and the column lengths may be unequal. The program will assume that the observations at the end of the shorter columns are missing.
A grid is drawn for each cell. The colour of the grid depends on the relative value of the cell. The cells with the lowest values will be coloured blue and the cells with the highest values will be coloured red. A scale of the colours used is shown on the right of the plot.