134 REPORT OF THE No. 3 



Work on this area was commenced in 1929. During the present season 

 however, a modification of previous methods was employed with considerable 

 success. Briefly, this consists of a combination of oblique photographic survey 

 and aerial sketching. The photographs, which must be taken and plotted a 

 season in advance, do not cover the whole area, but are laid down in a regular 

 system of strips. With this control system established, sketching can be 

 employed to fill in the gaps with a high degree of accuracy. At the same time, 

 Forest Types and details of topography hidden from the camera in the oblique 

 position can be added. 



Because of lack of uniformity in conditions, cost figures for Aerial Survey 

 vary a great deal and averages cannot be very closely applied to any specific 

 case. Records available, however, indicate that this procedure in the present 

 instance was no more costly than a straight sketching survey. The saving 

 results from the estimated saving in flying time for the combined operation, as 

 against a straight sketching survey. In so far as quality of the product is con- 

 cerned, there can be little doubt that the map produced by this method will be 

 more useful to the Branch than either a straight sketching or a purely photo- 

 graphic map. Accuracy of topographic data should in general compare very 

 favourably with a survey based on vertical photography. 



Summary of the status of this sftrvey at the close of the season of 1930 is 

 as below: 



Non-timbered 4,000 square miles 



Oblique photo strips run 8,000 square miles 



Forest types completed by sketching 4,000 square miles 



2. Photographic Survey: 



(a) Control for sketching in the Ogoki-Little Current Watershed. 



Eleven and one-half rolls of oblique photos, totalling approximately 

 eleven hundred exposures were used in this area. In addition, from the 

 same base, two rolls were exposed north of the Albany to obtain a general 

 idea of the character of the country and its timber conditions. This work 

 was based on oblique photography and is described in greater detail in the 

 section preceding in connection with Aerial Sketching. The actual area 

 covered by the photos approximates three thousand square miles. 



(b) Survey of Provincial Forests. 



Photography for these surveys was all vertical and totalled some six 

 hundred exposures. The reserves and areas in each are as follows: Eastern, 

 three hundred and fifty square miles; Mississagi, seventy-two square miles; 

 Kawartha, one hundred and sixty-two square miles. 



(c) Survey for Provincial Hydro-Electric Power Commission. 



Photos for this purpose were also vertical and totalled fifteen hundred 

 exposures. 



3. Radio Communication. 



During the past season, twenty-eight stations were operated by the Branch. 

 Of this total, four were located in the North Bay District, two in the Cochrane 

 District, two in the Sault District, three in Port Arthur, three in Kenora and 

 fourteen in the Hudson District. 



