98 A MANUAL FOR NORTHERN WOODSMEN 
(2) In timber estimating, the area of waste lands, heavy 
bodies of timber, etc., can often be obtained quickly ana 
with a fair degree of accuracy by this method, and these 
facts often furnish very great help in securing a close 
estimate. 
(3) The compass and pacing method is the cheapest for 
mapping roads, streams, ponds, and other topographic 
details in wooded country. For a real map, however, 
this method of survey should not cover too long distances, 
hut should tie into more accurate work. 
(4) Compass and pacing may be used to get a recon- 
noissance map of a region of any size, using a road or any 
other avenue of travel that passes through it. Not only 
the line of travel may be mapped, but the hills and other 
features of the country that can be seen. Cross bearings 
with the compass will locate them in the horizontal posi¬ 
tion, and the clinometer will serve to get their height. 
Specimen notes illustrating this method of work com¬ 
bined with the use of the aneroid barometer for determin¬ 
ing height, and a diagram showing how it is made to 
contribute to the production of a topographic map will 
be found on pages 126-128. 
✓ 
SECTION V 
THE TRAVERSE BOARD 
The plane table in its simplest form is called a traverse 
board, and consists of a square board without levels 
mounted on a tripod. On this board a sheet of paper 
is pinned, and the map is developed in the field. A 
compass needle set into the edge of the board serves to 
“ orient ” it, or, in other words, to fix one edge always in 
the north and south position. A brass ruler with vertical 
sights attached serves both to sight with and to draw lines 
and scale off distances on the map. It is called an 
alidade. 
A simple use for the board is to traverse a road, a 
stream, or the shore of a pond. Suppose, for instance, it is 
desired to survey a stream on the ice in winter, and a point 
