116 A MANUAL FOR NORTHERN WOODSMEN 
2. In securing an efficient map, a main principle to hold 
in mind is the relation between accurate and expensive 
work and work of a lower degree of accuracy. If elevations 
in a topographic survey were put in by level only, and 
horizontal positions fixed by compass and chain, an 
accurate result would be had, it is true, but it would be at 
enormous cost. On the other hand, the use of barometer 
and pacing alone might furnish a map so inaccurate as to 
be of little account. The effort must be to construct a 
skeleton of reliable points and lines, to which less accurate 
and costly work may be tied — to put points within reach, 
one might say, of the weaker method or instrument. Sur¬ 
veyor’s compass and chain, staff compass and pacing, and 
sketching form such a series in the horizontal determination 
of points. The level, the aneroid, and sketching are similarly 
related in height work. Sketching is the final term in any 
case, and much depends on it for both accuracy and 
appearance. In a way, it is easy, but real excellence in 
the art depends on a combination of eye, memory, and 
artistic sense. 
3. Throughout any ordinary work of this kind, it has to 
be understood that much detail is too fine for representa¬ 
tion or is really unessential, and on that account the 
topographer should neglect it. Makers of accurate maps 
neglect only what does not show on the scale of the map. 
Woodsmen will generally find it necessary to adopt a 
more liberal rule. 
The conditions under which forest mapping is done have 
an influence on methods in the following ways. 
1. Timber growth itself presents an obstacle to clear 
sighting. That favors the compass as against the transit 
for boundary work, and in the same way, in topographic 
mapping, triangulation and the vertical angle are put at 
a disadvantage as against methods which can be carried 
on under the cover of the woods. 
2. Forest topography should generally be tied to 
property boundaries, rather than to topographic promi¬ 
nences. Commonly, a survey of his boundaries is the first 
and most important work to be done for an owner who 
wants accurate knowledge about his land. It will, there- 
