Page:Graphic methods for presenting facts (1914).djvu/258

 Saturday Evening Post, Curtis Publishing Co.

Fig. 192. The 228 Principal Trading Centers in the United States

This illustration was taken from an advertisement proclaiming that a certain magazine's circulation was mainly in the 228 chief trading centers of the country, and that, accordingly, the magazine must be effective as an advertising medium for merchandise

Note that in the east the dots are so numerous they are shown as crescents. The crescent scheme is a good one as it permits the use of a much larger dot than would otherwise be possible

The amount of detail which may be permitted on any map in which pins are used depends on the size of the resulting illustration and the size of the pin heads. If the pins are so numerous that the map must be very large, there is danger of reducing the map so much in size between photograph and final illustration that the pin heads will appear as indistinct dots on the complex surface of the map. In Fig. 193 a map was used in which there was more detail than really necessary or desirable for a clear illustration. In justice to the General Electric Review it must, however, be said that the map shown in Fig. 193 has been reduced in size and made smaller than it was in the original print. This map could not be reduced further without danger of completely losing the pin heads in the gray background resulting from so many lines on the map.

In producing an illustration like Fig. 193 considerable ingenuity must be used to make two or more classes of pins show out distinctly in zinc cuts which can be printed in only one color. The pins on the