An object of class somgrid, such as the grid
element in a kohonen object.
phis
A vector of three rotation angles. Values for red, green
and blue are given by the y-coordinate of the units after rotation
with these three angles, respectively. The default corresponds to
(approximate) red colour of the middle unit in the top row, and pure
green and blue colours in the bottom left and right units,
respectively. In case of a triangular map, the top unit is pure red.
offset
Defines the minimal value in the RGB colour definition
(default is 0). By supplying a value in the range [0, .9],
pastel-like colours are provided.
Value
Returns a matrix with three columns corresponding to red, green and
blue. This can be used in the rgb function to provide colours
for the units.