PREPARATORY MAPS AND DATA 



19 



In 1909, the New York State Water Supply Commission * 

 made stadia surveys of three small areas of ground, the char- 

 acter of the work being similar to that required for preliminary 

 design of sewers in outlying territory of large cities. The work 

 included detailed topography, the location of all railroads, 

 highways, buildings, fences, etc. The three separate areas 

 were of 18.2, 56.1, and 21.8 square miles in extent, and the 



TABLE I 



SHOWING COSTS OF SURVEY NEAR CHICAGO 



Or 87 cents per acre. 



field work in each case cost almost exactly 75 per cent of the 

 total cost. The work was done by stadia and was plotted in 

 the field to a scale of 100 feet to the inch and then reduced in 

 the office to the smaller scale of 400 feet to the inch. 



The depth of rock and the character of the soil must be 



* Engineering-Contracting, Vol. xxxiii, p. 419. 



r OF 



Rc 



