NOTES OX STRIP MAPPING FOR INTENSIVE RE- 

 CONNAISSANCE. 



By a. F. Kerr. 



The objects of intensive reconnaissance are to secure: ist an 

 accurate map, 2nd an estimate of the timber, and 3rd other data 

 necessary for the proper management of the Forest — all at a rea- 

 sonable cost. 



The strip survey has been generally adopted as' the best system 

 for securing this information, for the following reasons : — The 

 gridiron arrangement of the strips permits of the simplest and 

 most effective methods of control, and the most accurate location 

 of details in mapping, and it fits well into the rectangular scheme 

 of the Land Office Survey. The gross estimates are practically 

 reduced to a mathematical basis, and may be worked up for con- 

 veniently sized, legal subdivisions. The application of correc- 

 tion factors for defect, etc., require judgment, but the bulk of 

 the estimating can be done by inexperienced and, consequently, 

 low-salaried men. 



The question of control is an extensive one in itself and, for 

 that reason, will not be considered here. 



In general the location of data on the strip map depends upon 

 pacing for distances and the aneroid barometer or Abney hand 

 level for elevations. Topography is shown by contours or form 

 lines drawn as the mapper proceeds along the compass course. 



This system is usually applied in one of two ways. Since the 

 Abney level is merely a substitute for the barometer in either 

 plan it need not be considered separately. 



By the one method which was commonly used, "form lines" 

 are drawn on each strip in accordance with the barometer 

 readings, and entirely independent of the form lines on adjacent 

 strips. That is, the form lines of adjoining strips are not con- 

 nected in the field but simply serve to indicate the direction that 

 the contours will take on the finished map. These form lines are 

 drawn on the map as' final contours, in the office, in accordance 

 with the "corrected" barometer readings. 



By the other method actual contours are drawn, and are con- 



