207 
Much of the work during and immediately before World War II in the 
USA was done at the Tennesse Valley Authority. One of them, Ralph 0. of 
Anderson (1947) proposed a scheme in which orientation of photographs (1 
would be done semi-graphically while the main scheme of control extension va 
would be done analytically. This, however, could not compete with pure tr 
analogical procedures primarily because of economic reasons. tl: 
cc 
During the war and the following years, the US Naval Photographic 
Interpretation Center developed a series of analytical solutions for camera 
calibration, space resection, interior and exterior orientation as well as co 
relative and absolute orientation of stereo-pairs (Merritt 1951). va 
f c 
At the US Ballistic Research Laboratories, Aberdeen, MD. as a ur 
consequence of research directed towards ballistic camera operations in ma 
which several cameras may observe an event simultaneously, the application me 
of these procedures into strip and block triangulation followed immediate- w i 
ly. These were primarily the efforts of Hellmut Schmid (1951 , 1954, 1959) w j 
who later joined the US Coast and Geodetic Survey. The principal features V e 
of Schmid's work are a rigourous least squares solution, the simultaneous ca 
solution of multiple photographs and a complete study of error propagation. 
Schmid (1974) was successful in extending his ideas in performing a three- 
dimensional geodetic triangulation by using passive (reflecting surface) U11 
earth satellites observed with ballistic cameras from 45 stations around 
the earth. He was probably the first photogrammetrist to look for solu- me 
tions in anticipation of the use of high speed computers (off-line). His 0 t 
early reports were written in vector notation. Later on he introduced £ a 
matrix notations. f c 
Su 
The first operational system of analytical aerotriangulation was 
developed at the British Ordnance Survey in 1947 with analytical radial 
triangulation in order to provide control for the large scale (1:2500) sc 
resurvey of Britain. This approach was abandoned in favor of using spatial ^c 
triangulation with reseau photography measured at the Cambridge Stereoscom- 20 
parator (Shewell 1953). The complete system modified in view of com- tr 
puter implementation was de-scribed by Arthur (1959). 
ds 
Paul Herget (1957) in his method of analytical control extension 
proposed the simultaneous solution of an entire strip but the eventual im- bl 
plementation of his system developed ultimately as a cantilever strip, ai] 
photo by photo. The Herget method, under contract from the US Engineer 
Research and Development Laboratories, and taken up by Cornell University, 
was next developed into a method capable of simultaneous solution of a \y 
block by way of utilizing either ground point or exposure station control (t 
(McNair et al 1958). This method was adopted by the US Geological Survey ma 
and developed, what is known, as the "Direct Geodetic Restraint Method" a = 
(Dodge 1959). de 
in 
There have been interesting developments in Japan (Ryokichi 1960) £t 
and in the USSR (Lobanov 1960) also apart from those in the European and pj 
North American countries. ev 
lv 
At the National Research Council of Canada, Schut (1957), among eq 
others, recognized the theoretical superiority of a simultaneous block tl 
solution but discarded it in favor of a cantilever strip formation because as 
be