the simplicity of the mathematical model on which the gener&l photogrammetric 
solution is based. Thus, the least squares solution, can be considered an 
economical technique for intersecting corresponding rays of various bundles. 
A comparison of this report with [2] ; Shows that the present approach 
distinguishes itself from the former one only by the way in which the elimi- 
nation of the unknown coordinates of the model X is &ccomplished. In the 
present solution, this elimination of unknowns is not performed algebraically 
before the observation equations are formed but during the process of forming 
the reduced normal equations. Consequently, the system of reduced normal 
equations (formula (37)) agrees, to all but second order terms, which have been 
neglected during the process of linearization by the Taylor series, with the 
corresponding normal equation system of the formerly published solution. The 
advantage of the present solution can be seen in the simple and systematic flow 
of the computations. It is possible to treat all casesvof practical analytical 
photogrammetry with but one basic computing scheme, thus simplifying consider- 
&bly the "bookkeeping effort" in the electronic computer. 
A critical study of the individual steps of the presented solution leads 
to a conclusion which, although somewhat discouraging for the author, may en- 
courage the application of analytical photogrammetry. It becomes obvious that 
the analytical treatment of photogrammetric problems does not call for any new 
manipulations in photogrammetric theory or statistical treatment of errors. 
The expressions, representing the basis of the whole solution, derived in 
equations (11) and (12), as they exist between the coordinates of the model and 
the corresponding coordinates of the images, are the well-known formulas derived . 
by v. Gruber in [14] and the corresponding inverse functions. The partial differ- 
ential quotients necessary to form the observation equations (15), given with‘ 
formulas (40) and (41) are the same expressions that are found in [1] or [?] ; 
the unmodified use of these expressions appears justified due to the simplicity 
of their construction. The system of normal equations (21) resulting from the 
system of observational equations (18) 1s identical, as mentioned before, with 
the solution given by Helmert in [4] . The elimination of the vectors, K in 
the system of normal equations (21), Ay in the system (35), and the reduction 
78 
Pp ae. *