1. A method for generating a combined parameter map, representing respective values of a combined parameter at all coordinate positions in said combined parameter map, from a plurality of initial parameter maps respectively containing values of individual parameters at respective coordinate positions in the respective initial parameter maps corresponding to said coordinate positions in said combined parameter map, comprising the steps of, for each of said initial parameter maps and for each of said coordinate positions: defining a first transfer function for a parameter in one of the initial parameter maps and converting a value of said parameter in said one of said initial parameter maps into a first color value using said first transfer function; converting said first color value into a color code intensity value using a second transfer function; operating on all color intensity values of the respective individual parameters in the respective initial parameter maps at each of said coordinate positions, to form a combined intensity value for that coordinate position; and converting said combined intensity value into a color code value, using a third transfer function, at each of said coordinate positions in said parameter maps.