Abstract: A display board for illustrating an electrical power distribution system or the like comprises a matrix of rectangular modules magnetically attached to a steel support board. The modules may comprise die cut steel base plates backed by sheets of magnetic rubber. Relatively permanent background graphics are silk screened upon the front faces of the modules. Foreground graphics representing features which are subject to change may be overprinted upon the background graphics in an ink which may be removed without disturbing the background graphics.

Abstract: A method of plotting a rectangular section of a regional image on a rectangular base plate. The base plate is positioned snugly in a frame having a recess of such a depth that the surface of the frame and the surface of the base plate define a substantially continuous surface. A CAD program is used to control a plotter to plot image information on the base plate and on the surrounding frame. The rectangular section of interest corresponds precisely with the image portion which is plotted on the base plate.