1. A computer system for using colors to graphically represent objects in computer screens, the system comprising: an object module which provides one or more objects each having attribute values; a distance calculator that calculates distances among the one or more objects and a target object, the target object having one or more predetermined colors; a color mapping module that assigns a color to the one or more objects based on the distance between the one or more objects and the target object, the assigned color being closer to the one or more predetermined set of colors at a closer distance to the target object; and an object rendering module that graphically displays the one or more objects by using the colors assigned thereto.