1921-22 DEPARTMENT OF LANDS AND FORESTS 249 



launching and testing the machines did not permit of regular flying until late 

 in May. From the outset, as had been confidently expected, it was apparent 

 that, largely because of the simple composition of the forest in this latitude, 

 type mapping could be carried on without further experience, in so far as the 

 separation of timber species and barren areas was concerned. These first 

 flights served also to show, what was amply borne out by subsequent exper- 

 ience, that the country presented a very excellent flying chance, being liberally 

 sprinkled with fairly large and well-connected lakes and free from any great 

 land elevations. Thus, the limitations of low performance were largely offset, 

 making it possible to fly with confidence and safety literally anywhere; and it 

 should be borne in mind that the successful operation of low performance 

 machines cannot be counted on without such favorable conditions. Flying 

 and forest conditions having thus been found suitable, and as the separation of 

 timber types and non-commercial areas was all the information required over 

 a large area, typing on this basis was commenced about June 4, and carried on 

 during the remainder of June and July. Weather conditions were ideal for 

 flying, so that by August 2, the mapping of some fifty thousand square miles 

 was completed to show the following types: 



(1) Coniferous stands, 75 per cent, of better coniferous species; 



(2) Mixed stands, less than 75 per cent, hardwood; 



(3) Burned-over areas partially restocking. 



5. Mapping Methods. — The system of mapping outlined below, was also 

 developed during this period, and was used throughout the season. 



The region being entirely unsurveyed — it might be said unexplored, if the 

 main canoe routes of the Hudson Bay Company were excluded — township 

 sheets for field sketching were not available, and it became necessary to pre- 

 pare field sheets. This was done by plotting the information recorded on the 

 eight mile to the inch Dominion Standard Topography Sheet for the region, 

 to a suitable scale, the scale finally adopted being one inch to the mile. Field 

 sheets, prepared as above, were attached to a drawing board and taken into 

 the air. Here, just as in ground work, the chief consideration in mapping is 

 to locate and orient the map. On the ground, by recognized survey methods, 

 this can be done either by scaling off a known distance on the line being run 

 and orienting by compass and back sight, or by orienting and intersecting for 

 position on points whose location is already known. In the air, location, in 

 the past season's operations and under aerial conditions generally, cannot be 

 had by the use of the most orthodox ground method, i.e., traveling on a line 

 whose length and direction are known. It should not be inferred from this 

 that aerial navigation is discredited, but it requires the constant attention of 

 a skilled navigator, besides the pilot, supplied with an assortment of complicated 

 instruments. Moreover, calculations are necessary, even with the fullest 

 instrumental equipment at present available; and the delay thus entailed, 

 however small, is a distinct drawback in aerial sketch work. On the other 

 hand, because of the greater number of such features, which can be seen at 

 one and the same time, position by reference to known physiographic features 

 can be obtained in flight more rapidly, accurately and easily than in the great 

 majority of cases on the ground. On the same basis and for similar reasons, 

 type lines can also be drawn in flight at a distinct advantage. In consideration 

 of the foregoing, mapping, during the past season, was carried on almost ex- 

 clusively by reference. 



