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 and 

 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, 

 but 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 130-132. 



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 



