Graphic Methods for Presenting Facts
Location of Water-Power Developments of 1,000 Horse Power, and Over, and Power Sections of Streams in the United States
The original of this map would have pins in two different colors. The photograph taken from the map would be retouched by the use of a pen so that squares would replace dots for one of the two colors of pins. The illustration shows a contrast of dots of two shapes rather than dots of two colors
GRAPHIC METHODS
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MAPS AND PINS 241
original map can be in different colors. After a photograph has been made of the pin map it is best to compare the photograph with the original, and then to make squares out of those circles which represent a certain color of pin on the original map. Squares are easily made by using a fine pen on a photograph considerably larger than the cut itself will be. When the final dots are not too small in size it is possible to make shapes with the pen such as triangles, outline circles, etc., which can be distinguished from one another.