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PHOTOGRAMMETRIC ENGINEERING 29 
as practical application by the Forest 
Service was concerned, the ideas presented 
simmered in the minds of many of his 
interested colleagues. 
In the early 1920's Lage Wernstedt of 
the Region 6 office in Portland, Oregon 
was experimenting with and proving the 
practicability of mapping mountainous 
areas from terrestrial photographs. The 
development of an improved type of 
panoramic camera by Osburn (of the same 
Region) aided Wernstedt in his work, and 
he later devised his own equipment for 
obtaining aerial obliques and mapping 
therefrom. It is generally acknowledged 
by Forest Service ‘‘old timers” that 
Wernstedt was the pioneer photogram- 
metrist of the Service, and that his ideas 
and capabilities were years ahead of his 
time. 
Meanwhile, several men in the Regional 
Office at Missoula, Montana had been 
trying unsuccessfully to finance the taking 
of vertical photographs for experimental 
work in mapping, timber, and grazing 
work. Their efforts were rewarded in 1926, 
when, with the assistance of T. W. Nor- 
cross (at that time Chief Engineer of the 
Forest Service), they obtained the loan 
of a 12 inch focal length, single-lens, 
military camera. With this camera, and 
with an improvised camera mount in 
the floor of a plane used for scouting forest 
fires, Howard Flint that same summer? 
took what were probably the first vertical 
aerial photographs for Forest Service use, 
covering an area of about 65 square miles 
of the Kaniksu National Forest. From these 
photos J. B. Yule (Chief of the Surveys 
and Maps Section) compiled a mosaic on 
a scale of 6 inches=1 mile. During the 
following five years, with Flint acting in 
the dual capacity of aerial fire scout and 
aerial photographer during the summer 
months, a number of small areas were 
photographed with borrowed military 
cameras. At the same time Yule was de- 
vising equipment and improving mapping 
techniques. By 1932 the results obtained 
had so impressed Region 1 officials that 
Yule was able to finance the purchase of 
a Fairchild K3B, 7'^x9"', 81 inch single 
lens camera,? believed to be the first 
aerial mapping camera purchased by the 
Forest Service. Very good planimetric 
maps were being compiled by the radial 
trip method at an extremely low cost, with 
home-made equipment devised by Yule. 
The 'underslung" projectors which Yule 
developed in 1930 are still being used for 
certain types of work, not only in Region 
1 of the Forest Service but by several 
other government offices. 
Other Forest Service regions were con- 
ducting experimental” work with aerial 
photos about the same time, and the in- 
fant 'aerial photography" was growing 
rapidly. In 1930? the Regional Office at 
Denver, Colorado issued the first Forest 
Service contract for a controlled plani- 
metric map to a specified accuracy. The 
Curtiss-Wright Flying Service was the 
successful bidder, but later the contract 
was sublet to Marshall Wright, Jack King, 
and J. W. Ninneman? who completed the 
work in the fall of 1931. In 1933? the large 
program for acquisition of land for national 
forests gave new impetus to ''Photo- 
grammetry" in the Forest Service, par- 
ticularly in the eastern and southern states 
of Regions 7 and 8. New techniques and 
processes were continually being devel- 
oped, and new equipment and machines 
aided the forest officer not only in mapping 
but in allied phases of work. Perhaps the 
first cadastral surveys by photogrammetric 
methods in the Forest Service can be 
credited to the work done at this time. 
J. B. Yule;?? in Montana, Washington, and 
Idaho had been utilizing General Land 
Office data identified on aerial photos, for 
control, and for outlining Public Land 
lines on the pictures for fire, timber, and 
grazing area identification. 
The Forest Service may well be proud 
of the contributions to photogrammetry 
made by its members. Wernstedt de- 
veloped a plotter, which although not in 
common use as such, embodied many of 
the principles of present day equipment. 
In 1941, after working on a test model 
since 1938, King, Elliott, and Kail® re- 
ceived a patent for their K.E.K. plotter, a 
relatively inexpensive machine for topo- 
graphic mapping and widely used today. 
The planimetric plotter devised by Philip 
B. Kail, and the several patents issued to 
J. E. King for photogrammetric equip- 
ment bear witness to the inventive genius 
of these Forest Service officers in their line 
of work. These machines are perhaps 
better known than the numerous other 
important devices and processes which 
have been perfected by Forest Service