- 59 - 
Charles THEURER 
îrial triangulation 
the advent of elec- 
e the growth of ana- 
sasurably. This con- 
vard photogramme- 
ictors in the data 
;omatic Point Mar- 
•ecise photographic 
sreocomparator that 
mages on each dia- 
if one micron. Iden- 
;o can be marked 
1 s console, two com- 
ts of air bearingta- 
g system, and a 
■ to operate the e - 
~ viewing the photo- 
)n will be discussed. 
:ks 
clearly indicates 
mmental techniques 
)duces some new 
n equal all-around 
rips, is advocated. 
Cantilever Sub- 
A full account of 
ub-Block Relative 
iccessive Relaxa - 
wly developed si- 
Photogrammetry of 
All the efforts that 
include : ( 1) aero - 
Corporation of Kan- 
* missiles and sa- 
vey ; (6) applica - 
-.and Management, 
special forms, ma- 
results. 
Approaching the Ultimate in Precision Photogrammetry 
The precision of photogrammetrically determined positions and elevations has been 
emphasized in the Coast and Geodetic Survey for the past four years. Analytic aerotriangulation 
has been used extensively for control extension on productive work. Monocular comparators and 
medium size electronic computers, utilized exclusively for the past several years, have been 
supplemented by stereoscopic comparators and large capacity computers. 
The general procedures in the application of both of these systems, including person 
nel training, instrument calibration, computational procedures, and analysis of results are 
described. Comparisons are made on the relative accuracy and productivity of each system. 
The same instruments and personnel engaged in analytic aerotriangulation are used 
interchangeably in the satellite triangulation program. The development of techniques for mea 
suring star plates and processing of data is described, indicating accuracy of results. Pro 
blems that were overcome and proposed solutions for those that remain are discussed. 
FINLANDE 
R. A. HIRVONEN 
General Formulas for the Analytical Treatment of the Problems of Photogrammetry 
Both exact formulas and approximate formulas for the practical use are given. Fol 
lowing problems are discussed. 1. The absolute orientation of a single photograph with three 
control points (pyramid problem). 2. The absolute orientation of a strip of photographs when a 
pair of relative control points is visible on three successive photographs. 3. Observational 
equations for the adjustment of strip and block triangulations. 4. Natural system of three-di 
mensional coordinates instead of a map projection with heights. 
It is suggested that an international recommendation be formulated for the definition 
of the three rotations of the camera, especially for the logical order of angles khi, omega, phi. 
Unto KORHONEN 
On the Azimuth Transfer Error of Aerial Triangulation Strips. 
The azimut transfer error, or bend, of the aerial triangulation strips is discussed. 
The author has carried out investigations in order to discover, what the exact cause for this 
error is and whether a Global Correction of the error could be determined in advance. A total 
of 90 strips consisting of c : a 2400 models over test areas have been computed and analyzed. 
It is well known that there are many sources of errors influencing the result of the ae 
rial triangulation, many of these error sources not yet being detected. In this investigation the 
author only could make distinction between errors of picture, errors of the measuring instru 
ment and the errors made by the operator. The errors of picture were investigated by measu 
ring photographs taken in various directions. The errors of the instrument were investigated by 
bridging in various directions. The errors of the operator were investigated by repeating the 
bridging of the same strip under unchanged circumstances. 
The investigation, which was for the main part made in the Photogrammetric Research 
Laboratory of the National Research Council of Canada, has resulted in a preliminary conclu - 
sion, that the main part of the azimuth transfer error is caused by the errors of picture. The 
errors of good instruments and those made by experienced operators have proved to play minor 
role. The investigation also indicates, that with very careful tests it is possible to determine a 
Global Correction to be used in bridging for small-scale mapping.