METHODS OF MAP MAKING 
123 
(see page 188), tying into the marks left. Elevations got 
by aneroid, corrected by barograph. Numerous modifica¬ 
tions of the rectangular system made as required. 
Alternative Methods. 1 . On roads the traverse board 
with chain is undoubtedly the best instrument for making 
a survey of fair accuracy. The compass and chain might 
also be used. But when streams are utilized, unless on ice, 
stadia measurement will be found to be best and quickest. 
2. The level might be dispensed with, and the transit 
used as a level on the same settings from which it is used 
to get bearing and distance. This works best on a stream 
with grade all one way, and, in the case of a party by itself 
in the backwoods, is probably the best means of getting 
data of this kind. One additional man is then required 
for maintenance. 
3. Instead of the strip survey, using compass and chain, 
compass and pacing may be employed with circular plots 
for the timber. It may also be better or necessary to 
discard both rectangular systems, and work out the topog¬ 
raphy by means of road lines, passes, etc., controlling 
features in the lumbering development. 
C. Subdivision and Topographic Survey Combined. 
The following procedure has been carried out on a con¬ 
siderable scale on undivided townships in New England. 
The methods employed have been found to be cheap and 
practical, and the maps resulting have stood the tests of 
use and time. 
1. Boundaries renewed and tract divided into sections 
by compass and chain. Topographic notes taken; chain- 
age marks left every quarter mile. Two months’ work for 
a party of seven men. 
2. Elevation of some point above sea level obtained, if 
possible; if not, datum plane assumed at or below lowest 
point on the tract. Level lines run over roads and streams 
to ponds, camps, and other accessible points, well distrib¬ 
uted through the tract. Commonly a week’s work for 
two men. 
3. Detail of topography and timber worked out together. 
Mountain peaks located by cross bearings; streams and 
roads by compass and pacing traverse; other features 
