TWENTY-FIVE YEARS OF PROGRESS IN PHOTOGRAPHIC INTERPRETATION 
; UNDER COMMISSION VII 
by 
Robert N.Colwell, Space Sciences Laboratory, University of 
California, Director, Berkeley Office, Earth Satellite Corporation, 
USA 
Introduction 
According to the famous poet-philosopher, Santellena, "Those 
who cannot remember the past are condemned to repeat it." As 
suggested by the title of this paper, however, there is a far 
less negative way of viewing the past 25 years of history in the 
field of photographic interpretation. In fact, the following 
might be considered as a parallel statement to Santellena's, 
except that it is one which quite properly accentuates the posi- 
tive rather than the negative in relation to photo interpretation: 
"Those who can remember the past can exult in it and build upon 
it." Rather than feeling condemned to repeat the past, we should 
find it a great deal more uplifting and challenging to strive for 
as much progress in the next quarter century as has been achieved 
in the most recent one. 
The assertion that photo interpretation progress has been usually 
great during the past quarter century implies that progress in 
this field was significantly less in prior times. Indeed, that 
appears to be what history tells us. Such a conclusion was for- 
cibly brought to my attention recently as I prepared a paper 
that was much farther ranging than the present one. That paper 
was entitled "History and Future of Remote Sensing Technology 
and Education" (Colwell, 1978). As documented quite fully in that 
paper, but also as indicated in the next section of the present 
paper, it was as the aftermath of World War II that progress in 
photo interpretation and related fields accelerated very greatly, 
indeed. In my opinion most of this progress would not have come 
about except for a great surge of interest in these fields during 
the post-war period on the part of scientists in a great many 
disciplines. By way of setting the stage for the sections which 
follow, therefore, let us first examine the evidence that there 
has, indeed, been such an increased interest. 
Anyone who has had the exhilarating experience of attending the 
annual national meetings of his professional society is likely 
to have gained the impression on each such occasion that his 
profession is growing by leaps and bounds and is commanding the 
interest of most of the entire thinking world. For example, with- 
in the United States this is exactly the feeling that many remote 
sensing scientists have received, year after year, at annual 
meetings of the American Society of Photogrammetry, as they have 
talked with their fellow workers about the future of photography, 
photo interpretation and other aspects of remote sensing. With 
the benefit of 20/20 hindsight those of us who are the "old 
timers" now can perceive that, until the beginning of the post- 
war era, most of what we were experiencing was little more than 
a warm glow at being in the presence of some hardworking pro-