204 
of overlap between adjacent models) the two intersections in individual 
models must take place at the same spatial location. This condition is 
always used in conjunction with the coplancirity equations. 
Theoretical concepts of bi-projective transformation (Das 1952) 
and the^use of distances in the object space as control for stereo-models 
(Das 1J73, Okamoto 1981) are purely computational approaches that would 
prove extremely efficient in various applications of stereophotogrammetry. 
6.2.3.4 Related to Multiple Images 
The application of analytical procedures on which most discussions 
and efforts have been made is that of phototriangulation. As early as the 
beginning of the World War II, the need was typified in the following 
quote (Schermerhorn and Neumaier 1939): "The problem of control points 
was and is still, to a certain extent, the bottleneck in photogrammetric 
map production". Initial efforts were with regard to the adjustment of 
analog aerotriangulation. Later efforts concentrated on fully analytical 
procedures. Their classifications and consequent historical developments 
would be apparent in Fig. 6.2 
Fig. 6.2 
A. Adjustment of Analog Aerotriangulation 
Historically, the development may be noted in terms of three 
stages: 
Stage 1 : Adjustment of individual strips along with associated data 
analyses and interpretations. The works of Thompson (1953), 
Roelofs (1949) and Gotthardt (1944) give typical indications of the 
initial studies. One would notice at this stage the prolonged 
discourses on the causes and propagation of random errors over 
those of systematic errors. One can refer to one single publi 
cation to typify the culmination of this stage in the OEEPE (Orga 
nisation Européenne d'Études Photogrammétriques Expérimentales) 
report for studies up to the end of 1959 (Solaini and Trombetti 
1961). This study, initiated in 1956, concerned international 
efforts at twelve research centers and analyzed the results of 
some dozens of strip triangulations by using different adjustment 
procedures. 
Several scientists got involved in such studies in the OEEPE 
group or separately and left their marks in numerous publications 
of each of them, such as, W.K. Bachman, A.J. Brandenberger, A. 
Bjerhammer, A. J. van der Weele, A. Verdin, P. A. Yermeir, J. 
Zarzycki and M. Zeller. The efforts of the ISP Commission III in 
this regard were very significant (see Cassinis and Cunietti 1964). 
The OEEPE (1973) publication indicates the termination of experi 
mental researches of this stage, having the attention already 
passed from the treatment of isolated strips to that for an entire 
block. The highlights of this stage were: (1) Adjustment of 
aerial strip triangulation was approached by using condition equa 
tions; (2) The least squares principles were being applied to the