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————— M
PHOTO INTERPRETATION IN EARTH SCIENCE
probable that this method has been at least partly responsible for the discovery
of many new oil fields. In the mining industry, the use of air photos is perhaps
less extensive, but experimentation is in progress, and one major new discovery
of iron ore, Cerro Bolivar in Venezuela, was made directly on the basis of
photo interpretation (Lake, 1950). In highway engineering, photo interpretation
has been found to make for increased economy and efficiency of operation in
many ways. In other fields of engineering, less specific information is available,
but it can be said that photo interpretation is assuming a role of increasing
importance. This is particularly true of arctic regions, where the peculiar
problems imposed by the occurrence of “permafrost,” or perennially frozen
ground, require very specialized methods of procedure, and very careful selec-
tion of sites for engineering operations.
Another benefit which arises from photo interpretation, aside from expediting
routine mapping and various practical applications, is the discovery of research
problems. Unusual or anomalous features found on photos sometimes raise
questions which cannot be answered from current knowledge, and thus lead to
investigations which enlarge our understanding of earth phenomena.
In view of the importance of photo interpretation, it is pertinent to consider
briefly the existing training facilities in this field. At the present time, these
facilities are by no means adequate. Elementary courses in the use of photos
are given in some of the more progressive colleges and universities, but it is
probable that only a minority of the geologists and engineers now graduating
receive such training. Many oil companies and other organizations find it neces-
sary to provide their own training for new employees. A viewpoint frequently
expressed is that well-rounded training in the fundamentals of a professional
field is more important than specialized training in photo interpretation proper,
and it probably is true that the best field geologist or engineer will make the
best photo interpreter. As in many other fields, experience is, within certain
limitations, the best teacher, and the more advanced phases of photo interpre-
tation are best learned by practice, with opportunity to check results. A proper
formal introduction to elementary photogrammetry and to interpretation,
however, does make it possible to profit more rapidly and more fully from
experience, and to be alert to opportunities for acquiring beneficial types of
experience. Expansion in training facilities is overdue.
From the over-all viewpoint, present trends are toward more extensive and
intensive application of photo interpretation in the various fields of earth
science, toward better evaluation of its capabilities and limitations, and toward
results of greater reliability. In certain quarters, there is perhaps a tendency
to expect too much from photo interpretation, to regard it as a panacea for all
manner of problems. Although this can be expected to lead only to disap-
pointments and temporary setbacks, fortunately it is not a widespread attitude,
and it may, indeed, be regarded as a part of the usual growth cycle of a new
field, leading ultimately to a better appraisal of its proper functions.
In order to utilize photo interpretation with maximum effectiveness, and
provide an adequate foundation for it, much remains to be done. Further re-
search and experimentation is greatly needed in many phases of the subject.
The compilation of reference works or manuals showing the typical surface
expression on photos of a wide range of natural phenomena, well known from
the ground view, would be most helpful. And there is a pressing need for more
and better dissemination of information on photo interpretation at all levels.
Potential users need to learn of the advantages which it offers, and interpreters
have much to learn by pooling their experiences and studying one another’s