Page:Graphic methods for presenting facts (1914).djvu/257

 purposely photographed at an angle of about 45 degrees. As the upper part of the illustration is out of focus because of the angle, the illustration does not do justice to the Government maps. Another reason why the map does not come out clearly is that brown ink is used to print the contour lines and these lines accordingly show only faintly in the half-tone.

When it is necessary to show the routing to various points on a map the best method is to use a fine red string or thread between map pins as seen in Fig. 191. If the routing must be changed the thread can be almost instantly moved to connect the pins in some new order. Lines could be drawn on a map in ink to show routing, but the map would be ruined if any change in routing should ever be necessary.

In the preparation of illustrations for reports, advertising, etc., whether maps with or without pins are used, great care must be taken in the selection of the map itself. Map manufacturers have a very annoying custom of purposely making maps in such manner that the maps cannot easily be duplicated by photographic processes. Maps printed in blue ink are almost hopeless for use in making zinc cuts. Maps on which large areas as States, or counties, are differentiated by the use of colors red, orange, green, etc., do not produce either good line cuts or good half-tones since the colored areas on the original maps are likely to show as solid black areas and blot out all detail on the photograph. If an illustration must be made from a map it is well to be sure that the map is printed in black, red, or orange outline so that the resulting photograph will have distinct contrast. Maps should contain as little detail as practicable, to make certain that the pin heads or other representations of specific data will show up as distinctly as possible. Fig. 192 is a good example of the kind of map to use for reproduction when pins are employed. Notice in Fig. 192 a heavy border for the country as a whole, and the outlines for each State. Towns and rivers are not shown. Each dot on the map may thus be seen with great clearness.

As maps are very carefully copyrighted by most map publishers, maps which are copyrighted should not be reproduced without consideration of the copyright. For maps which are photographed down with comparatively little change, permission should be requested from the map publisher, to make certain that unpleasant complications such as damage suits or the holding up of a publication may be avoided.