trees more clearly, to position these features, and to read eleva 
tions on them. In our airport work, we are finding that the 
color photography is generally superior to panchromatic for the 
stereoscopic measurement of elevations in all types of terrain 
and I feel that this is going to be one of the principal advantages 
of color photography for topographic mapping. The tests being 
made by the Geological Survey will provide more information 
about this and I look forward to their report with great interest. 
Increased Illumination for the Stereoscopic Instrument: 
Color photography of good contrast and interpretability is more 
dense than panchromatic and we found it desirable to increase 
the illumination on our B-8 plotters. We could have processed 
the color diapositives so as to reduce the density but this would 
have reduced contrast and interpretability with a partial loss 
of the advantage of color. At our request, the Wild Instrument 
Corporation made a study of this problem and arranged for the 
Richards Corporation of Arlington, Virginia, U.S.A., to make 
new lights for the B-8 plotters that provide for a variable illu 
mination from 1 to 10 times greater than the original illumina 
tion on these plotters. These are cool, gas-tube lights arranged 
in a grid pattern with rheostat control. They do not require a 
cooling system. We are installing these lights on all of our B-8 
plotters and think they will improve the viewing of panchro 
matic as well as color diapositives. 
Acknowledgements 
In the preceding sections I have endeavored to summarize 
our present practices in processing and using color photography. 
We did not arrive at this present position without effort, and in 
closing this discussion, I take great pleasure in acknowledging 
the assistance that I have had in my own shop and the assist 
ance that we have had from industry. Mr. William D. Harris, 
Chief of our Research and Development Branch, and Mr. John 
T. Smith, Chief of our Air Photographic Laboratory, have 
provided the technical competence, initiative, imagination, 
and persistence needed to work out our system in the Coast and 
Geodetic Survey. We, however, can only use the materials and 
products developed and produced by industry and could have 
made little or no progress in this effort without the assistance of 
the General Aniline and Film Corporation and the Eastman 
Kodak Company. Both of these organizations have observed our 
operations, worked with us in our laboratory, and have been 
willing, in their research and development, to gamble on the 
future of color photography for metric photogrammetry. When 
we started this work in 1958, films then available were not 
adequate for this purpose. Ansco gave us our first boost by 
spooling their Super Anscochrome film for aerial photography. 
The improved speed, lower granularity, and higher resolution of 
this film convinced us of the future of color photography. Since 
that time, of course, Ansco have produced their FPC-132 film 
and later Anscochrome FPC-289 film. Meanwhile, the Eastman 
Kodak Company improved the older Aero Ektachrome through 
several stages and recently produced the Kodak MS Ektachrome 
film. And, as I mentioned earlier, the Eastman Kodak Company 
recently forged the last link in metric photogrammetry by 
providing excellent color diapositive plates. 
INFRARED PHOTOGRAPHY 
In conclusion, the advantages of infrared photography for 
mapping any shoreline contour such as the mean-low water line 
or the mean-high water line are amply illustrated in Figures 2 and 
3 and need little discussion here. We use tide-controlled infrared 
photography for mapping the shoreline for boundary purposes, 
and for nautical charting purposes. 
For nautical charting, we find that it often pays to take 
tide-controlled infrared photography to determine the mean-high 
water line, which is our shoreline for charting, and tide-controlled 
color photography at mean-low water to map the foreshore and 
slightly submerged alongshore features. The time and cost for 
this duplicate tide-controlled photography are repaid many times 
by the reduction in the volume of field work that was formerly 
required for mapping an intricate shoreline. 
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