The aerial photograph contains a complete panoramic record of surface geologic conditions, alleviating 
extrapolation of data. Conventional B & W aerial photography has been used for more than thirty years as 
geologists began to realize the value of the vertical, stereoscopic perspective for geologic observations. 
Recent developments in various types of color photography have provided a broader dimension and range to 
the aerial camera as a tool for the detection and assessment of the earth’s natural resources. The advantages 
of color over conventional B & W photography in natural resources exploration are vividly demonstrated in 
several selected examples. : 
38. Viberg, L. 
Sweden 
GEOTECHNICAL INTERPRETATION OF AERIAL PHOTOGRAPHS - A STUDY 
OF THE RELIABILITY OF THE METHOD 
Geotechnical interpretation of aerial photographs is becoming a valuable aid in general soil investigations, 
primarily in connection with urban and road planning. It is being applied for the special purpose of mapping 
different types of soil and their limits, as well as for estimating relative depths of fine sedimentary deposits. 
Aerial photographs are also used for the layout of geotechnical drilling programmes. 
In order to get an idea of the realiability of aerial photo interpretation for determining the distribution and 
limits of different types of soil, a study has been made of the results obtained from the analysis of aerial 
photographs as compared with geotechnical and geological field surveys of the ground. For the purpose of the 
study some areas previously investigated on the ground were selected. The regions studies were Maiardalen- 
Sodertorn and the southwest part of Sweden. 
The comparison has included the identification of different soil type areas and their boundaries, as well as an 
estimate of the relative depths of the fine-grained sediments. In the identification the following soil type 
classification has been used: rock outcrops, moraine, coarse sedimentary deposits (sand, gravel and pebbles), 
fine sedimentary deposits (clay and silt), organic deposits (organic clay and silt, muck and peat). 
39.  Zsilinszky, V.G. 
Canada 
RESOURCES SURVEYS WITH MINIATURE CAMERAS 
Supplementary aerial photography with motorized 35 mm cameras provides imagery with extensive and 
economical photographic capability considering a variety of scales, seasons, multispectral sensitivity and 
subjects. The Ontario Ministry of Natural Resources uses such a versatile system. Common operations are 
cutover and road mapping, and delineation of infestation and pollution. Special projects are sampling of 
timber stock, plantation success, nursery seedbeds, beaver population and many others. These activities are 
reported and findings are discussed. 
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