THE STATUS OF PHOTO INTERPRETATION 
IN PETROLEUM GEOLOGY 
Robert L. Anderson. 
The use of air photographs and their interpretation by stereoscopic methods 
have constituted one of the outstanding developments in petroleum exploration 
during the past few years. Photographs have naturally provided the best possible 
mapping base in regard to accuracy and faithfulness to detail. The logical 
development of stereoscopic interpretation of these photographs was in accord 
with the general feeling of the need for a more rapid method of evaluation, 
which would remain within budgetary limits. 
The companies engaged in petroleum exploration have long been known 
to be uncommonly ingenious in the efficient utilization of resources, of men, of 
ideas and methods. It would follow then, that leaders in this highly competitive 
industry would turn to the uncommonly ingenious photographic methods of 
exploring the wrinkled face of this old earth. And so they have. 
The acceptance by most major oil companies of photo interpretation for 
geologic reconnaissance leading to the discovery of potential prospects has now 
become nearly universal. The advantages are several. It is rapid, it is con- 
fidential, and the overall cost remains low. The geologist, given wings as it 
were, is able to observe more outcrop area and the structural relations of those 
outcrops in an overall pattern than he could possibly observe on the ground. 
He does so in less time and with much clearer understanding. Further, the 
geclogist is able to evaluate areas without disclosing to competitors the nature 
or extent of interest of the company. Finally, the cost of such an evaluation is 
usually far below the cost of older, more conventional methods. 
The acceptance of the method has become so universal that there are few 
companies engaged in petroleum exploration that do not use it. Indeed, several 
companies have organized and are operating their own sections of photo inter- 
pretation within the geological departments. In addition, there are companies 
and individuals doing photogeology on a service basis. 
Nearly all the actual, or potential, petroleum provinces are amenable to 
photogeologic evaluation, and experience has indicated that photography brings 
out geologic relations which in the field are at best obscure and often missed 
completely. At the present time, areas are being successfully interpreted that a 
few years ago, due to the lack of that experience, would have been most diffi- 
cult if not impossible. Obviously, photogeology works best where the forma- 
tions are well exposed. Arid, folded regions, such as large parts of the Rocky 
Mountain area of the United States, are ideal. The same is true of large parts of 
the middle east, but as our experience and knowledge of the skill of photogeol- 
ogy have grown, the sphere of our ability has also grown until, at the present 
time, some form of photo interpretation is nearly global in usefulness. Foreign 
areas where accessibility is difficult present unlimited possibilities for future 
photogeologic exploration. 
The specific objective of photo interpretation in this field is well known 
and without any peculiar mystery or attempt to be complicated. Insofar as geo- 
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