63 
Chapter V 
C) REPORT ON THE PARTICIPATION OF THE DEPARTMENT OF 
GEODETIC SCIENCE THE OHIO STATE UNIVERSITY 
COLUMBUS 10, OHIO, U.S.A. 
Test N. 17 
by 
Dr. Arthur Brandenberger 
Professor 
1 — DESCRIPTION OF THE TEST PERFORMED 
1. Characteristics of The Block Triangulation « Massif Central ». 
At the conference of Commission III (Aerial Triangulation) of the International 
Society of Photogrammetry in Brussels, Belgium, May, 1958, it was decided to perform 
experimental research on a block triangulation located in the « Massif Central » in 
France. It was the aim of this research to investigate whether such a block triangul 
ation would yield a sufficient accuracy of control points to compile maps in the scale 
1:100000. For this purpose a standard residual planimetric error (root mean square 
error) of 15 meters and a standard residual elevation error of 5 meters were 
considered as tolerances. 
The block triangulation consists of three principal strips (tie strips), T-1, T-2, 
and T-3, and eight longitudinal strips (filler strips) 1, 2, 3, 4, 5, 6, 7, and 8 (see Fig. 1). 
In this figure the ground control points (A) which were used for the adjustment 
of the block triangulation are also indicated. 
The ground elevations in the block triangulation vary, between 300 m and 1600 m 
above sea level, and the average ground elevation amounts to 800 m above sea level. 
Vertical photography, from approximately 9000 m above sea level, was taken 
with a Wild RC7 Plate Camera with a nominal focal length of 100 mm and a photo 
graph format of 140 X 140 mm. The forward overlap and the sidelap between adja 
cent longitudinal strips amounts to approximately 70 per cent and 15 per cent respec 
tively. For the flight altitude used, an approximate picture scale of 1:80 000 is obtained. 
The average number of models per principal strip amounts to approximately 28.