If it is not necessary to photograph the map, pins with different colors of heads may be used to show density of population. There is one very great advantage in using pins instead of crayons or the pen-and-ink system , of Fig. 181. It sometimes happens that an error is made which may spoil a very valuable map because of the impossibility of erasure. When short pins are used instead of crayon or ink, an error can be instantly

GRAPHIC METHODS

o ff T A n z

tr'\j^>~~- ,...-i-r-; ^ ' /

W'-'' '■•■ '; ' J \ '^ I

los*v<e<io;^^»i-^ creek; ; ^ pvE*^* I u-- -' -- V \ Ji

6x7;

IJFUuoii n(E>pfflE

■ /*r y£RHON %

Wm. Plerrepcmt White, of Utica, N. Y., in the New York Tlrnea

Fig. 182. Map Showing 3,500 Miles of Completed and Proposed State Roads, in New York's Proposed 12,000-Mile System. The Shaded Portion Shows a Strip Ten Miles Wide which Contains 90 Per Cent of the Taxable Valuation and 80 Per Cent of the Population

The object of the illustration is to show the necessity of a road system that will feed from the farms to the densely settled portion, permit the quick and easy transportation of farm products to the cities, lessen the cost of living, and thus justify the taxing of the State as a whole for the construction of this system

corrected by pulling out pins. Also, if there should be a reduction in the density of the population, pins can be pulled out, whereas with the pen-and-ink method of Fig. 181 it is not possible to proceed backward on the scale of marking and a decrease can never be shown without making another map or marring the old one.