John D. MAYER 
New Developments in Equipment for Analytical Photogrammetry 
Previously the mathematical computations required in analytical aerial triangulation 
were much too involved and time consuming for military applications. With the advent of elec 
tronic data processing systems and their general acceptance for military use the growth of ana 
lytical photogrammetric procedures in the military regime was helped immeasurably. This con 
cept required a complete re-examination of the mathematical approaches toward photogramme 
tric solutions or more particularly a re-evaluation of the errors and time factors in the data 
acquisition instrumentation. 
This paper is presented to describe one such development. The Automatic Point Mar 
king, Measuring and Recording Instrument’has been fabricated to provide precise photographic 
coordinate data very rapidly. This equipment is essentially an electronic stereocomparator that 
has the capability of matching images electronically, marking the selected images on each dia- 
positive, and measuring the coordinates of the images with a least reading of one micron. Iden 
tification error is expected to be eliminated and it is expected that each photo can be marked 
and measured in less than five minutes. The system consists of an operator’s console, two com 
parator units, and a three-unit electronic rack. The comparator unit consists of air bearing ta 
bles with Ferranti measuring system, an electronic scanning and correlating system, and a 
marking system. The operator's console contains all the controls necessary to operate the e- 
quipment including visual read-out of the coordinate data, a monitor tube for viewing the photo 
graphic area being scanned at the tables. Equipment operation and application will be discussed. 
Descriptive slides and test results will be presented. 
Edward M. MIKHAIL 
Analytical Aerotriangulation : Two-Directional Triplets in Sub-Blocks 
A study of past and current methods of analytical aerotriangulation clearly indicates 
the close similarity in basic thinking between analytical treatments and instrumental techniques 
of triangulation. In this paper, the author reappraises the situation and introduces some new 
concepts and ideas that are more suitable for analytical photogrammetry. An equal all-around 
overlap, thus allowing for forming square units or sub-blocks, instead of strips, is advocated. 
For this sub-block approach, two methods of solution are presented : (1) " Cantilever Sub- 
Block Extension " and (2) " Sub-Block Best-Fit by Relaxation Procedure ". A full account of 
the second method is presented. It is composed of the following steps : (a) Sub-Block Relative 
Orientation, (b) Sub-Blocks' Assembly, and (c) Adjustment to Best-Fit by Successive Relaxa 
tion. On the third step best results appear to be obtained making use of a newly developed si 
multaneous three-dimensional transformation of higher degree. 
G. C. TEWINKEL 
Computational Photogrammetry in the United States 
This paper comprises a report of the Committee on Computational Photogrammetry of 
the American Society of Photogrammetry by the chairman of the committee. All the efforts that 
have come to the attention of the committee will be described briefly. Thes include : (1) aero 
triangulation in the U. S. Coast and Geodetic Survey ; (2) by the Utility Data Corporation of Kan 
sas City ; studies at the I. B. M. Laboratories ; (4) ballistics applications for missiles and sa 
tellites ; (5) geodetic satellite operations in the U. S. Coast and Geodetic Survey ; (6) applica 
tions at the Army Map Service ; (7) cadastral applications by the Bureau of Land Management, 
etc. . In each instance the application will be described relative to its type, special forms, ma 
thematical formulas, instrumentation, computers, volume of operations and results.