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PHOTO INTERPRETATION PICTURE, COLWELL 91 
gate attending these meetings to select intelligently the sessions most worthy of his 
attention. 
2. The first definitive book on photo interpretation has been prepared. 
Eight years ago, just as the International Society for Photogrammetry was con- 
vening in Washington D.C. for its Seventh World Congress, the American Society of 
Photogrammetry published its first comprehensive edition of the Manual of Photogram- 
metry. (Although there had been an earlier edition, consisting mainly of a compendium 
of previously published papers, it had been offered with some apology by the Society and 
had been termed merely a *preliminary" edition.) The favorable reaction to this Manual 
of Photogrammetry prompted many suggestions that the Society should prepare a com- 
panion volume to it, to be called the Manual of Photographic Interpretation. I was asked 
by the American Society of Photogrammetry to poll representative members of the Soci- 
ety to determine their attitudes regarding the desirability of such an undertaking. To 
my surprise, many photo interpreters and a few photogrammetrists stated quite un- 
equivocally that it would be a mistake to attempt to prepare a comprehensive Manual of 
Photo Interpretation until this relatively new field had “come of age” and matured suf- 
ficiently to permit such an undertaking. In addition, several photogrammetrists, and a 
few photo interpreters, expressed the opinion that this was not an appropriate under- 
taking for a Photogrammetry Society, regardless of the state of the photo interpretation 
art. In effect, these individuals were seriously challenging the validity of the optimistic 
remarks I had just made about the “newly acquired stature of photo interpretation” and 
the fact that “its value is widely recognized”. In the face of this dissent, however, there 
were even more Society members who thought that preparation of a Manual of Photo 
Interpretation should be started immediately. Work on the Manual was begun a short 
time thereafter, and a few chapters were ready for review in rough draft form at the 
Eighth World Congress in 1956. 
Now, as the International Society for Photogrammetry convenes for its Ninth World 
Congress, the American Society of Photogrammetry brings forth its first edition of the 
Manual of Photographic Interpretation. Pre-publication sales and reviewers’ comments 
indicate that this Manual will be fully as popular and valuable as the Society’s Manual 
of Photogrammetry. 
Some members had been concerned lest the Society’s “photo interpretation tail" be 
guilty of wagging the “photogrammetry dog” as a result of this undertaking. In a sense 
this concern was well justified because publication of the Manual of Photo Interpre- 
tation has been almost twice as costly, triply as time-consuming, and fully as interest- 
commanding as any other activity andertaken by the American Society of Photogram- 
metry in its twenty-six year history. But it would seem that in the American Society, as 
in the International Society for Photogrammetry, where photogrammetrists and photo 
interpreters have been working in mutual support of each other's interests for many 
years, there are now far more fruitful matters for consideration than the question of 
where the photogrammetry dog leaves off and where the photo interpretation tail begins. 
It is hoped that the Manual of Photo Interpretation in its published form will serve to 
convince even the most skeptical photogrammetrists that the Society's great efforts and 
eostly expenditures in preparing and publishing this Manual were not only appropriate, 
but eminently worthwhile. 
At the time of this writing, while the Manual of Photo Interpretation is still on the 
presses, I happen to be far more familiar with it than anyone else, having served as its 
editor during the period required to prepare it. If the Manual enjoys even a small frac- 
tion of the success that I predict for it, we can safely assume that photo interpretation 
has truly come of age, and has established itself as a worthy ally of photogrammetry, 
the critics notwithstanding.