WORKING GROUP 5 
TOMLINSON 
281 
The final group of techniques concerns the photo interpretation of detailed 
geographical problems. 
I have in mind present studies, such as that relating periglacial features to 
existing lakes in northern Canada [54], or the recognition of lichen concen 
trations which appear as distinct areas on aerial photographs at a scale of 
1 : 20,000, and are related to the existence of snow patches 200-300 years ago; 
or the close time cycle photography which allows a synoptic study of tide 
pulse movements [7], or the detailed examination of periglacial forms from 
photographs at a scale of 1 : 10,000 [8]. 
In some of these cases the photograph is being used as the fundamental 
research tool in a way that no amount of fieldwork can replace, as relationships 
are being observed that are only apparent on the air photograph. It is perhaps 
in this field that the most significant advances in geographic photo inter 
pretation have yet to be made. 
Conclusion 
It will be seen that photo interpretation applied to geographical studies in 
Canada has been successful when applied to the static inventory. Particularly 
has this been the case in large scale survey and the reconnaissance type survey 
where it has provided the primary geographic statement of many areas. 
Development in this area can be looked for in the use of air photo interpre 
tation for reconnaissance regional synthesis rather than analysis - and this may 
be aided by stereoscopic examination of high level RC.9 photography with a 
negative scale larger than 1 : 150,000. 
Use of air photo interpretation in small scale studies is most successful when 
the photography is of suitable scale and age. Despite Canada’s coverage and 
availability of air photographs, it is felt that the lack of suitable photography 
has been of considerable significance in the development of geographic inter 
pretation and that much more can and will be done, as the use of the photo- 
interpretive study proves itself, and as additional photography planned and 
times for interpretive studies becomes available. 
References 
1. Bird, J. B. Physiography of the middle and lower Thelon Basin. Geogr. Bull. 1, 1951. 
2. Bird, J. B. Southampton Island. Geogr. Branch Memoir. 1, Dept, of Mines and Techn. 
Surveys. Govt, of Can. 
3. Bird, J. B. Terrain conditions in the central Canadian Arctic. Geogr. Bull. 7, 1955. 
4. Bird, J. B. Air photograph interpretation key for Bathurst Inlet area, District of Macken 
zie, Northwest Territories, Canada. Ottawa 1955. Typed MSS. Prepared for Geogr. 
Branch, Dept, of Mines & Techn. Surveys. 
5. Blake, W. Vegetation and physiography of the Goose Bay area, Labrador, and the inter 
pretation of forest cover types and land forms from aerial photographs. Unpubl. M.Sc 
thesis McGill Univ. Montreal 1953. 
6. Bridgeland, M. P. Photographic surveying, Canada. Interior Dept. Topogr. Survey, 
Bull. 56. Ottawa, 1924. 
7. Cameron, H. L. Interpretation of high altitude small scale photograph. The Canadian 
Surveyor XV, 10, 1961.