has to 
iliary 
is ap- 
first 
ained 
)hoto- 
hs of 
rofile 
tment 
tment 
mtrol 
ed to 
lows 
t the 
addi- 
npler 
from 
lered 
ented 
0 the 
; are 
stru- 
addi- 
f the 
'tical 
tions 
lelap 
| re- 
10del 
se of 
nake 
cope 
s an 
10re, 
and 
ere 
  
AERIAL TRIANGULATION WITH AUXILIARY DATA, BRANDENBERGER 91 
longitudinal tilt information. Test performed with this procedure proved to be satisfactory. 
The strip triangulation procedures with auxiliary data which are used in France have 
been fully explained at the Stockholm Congress and at the International Conference on 
aerial triangulation in Ottawa 1957. In these procedures auxiliary data are only used 
for adjustment purposes and not during the triangulation in the stereoplotting instru- 
ment. Since 1956 several block triangulations with Statoscope data were performed. How- 
ever, no accuracy indications can be given since no test points were available. Ample 
information on accuracy will be available when the actual experiments under the super- 
vision of Committee III will be terminated. The results of these experiments will be com- 
municated at the Congress in London. Mr. Bonneval states that the average time required 
per model is exactly the same for strip triangulation with or without auxiliary data 
(aerial polygon method). This time amounts to about two hours when first order stereo 
plotting instruments (Poivilliers type B) are used, and forty-five minutes when analytical 
strip triangulation (stereocomparator Nistri) is applied. No significant cost difference 
is found between the strip triangulation with or without auxiliary data. 
Germany 
Dr. Brucklacher from Germany reports that since 1956 various strips with stato- 
scopes were flown in Germany. This material serves as basis for studies in the field of 
aerial triangulation with auxiliary data. Statoscope data are introduced as altitude dif- 
ferences in a first order stereo plotting instrument and instead of bz both ¢ are used 
for the relative orientation (aerolevelling method). For the determination of the altitude 
differences with respect to a convenient datum the slope of the isobaric surfaces is taken 
into account. For this purpose information from meteorologic stations are required. Dr. 
Brucklacher gives some information about vertical adjustment of strip triangulations 
with statoscope data. Two ground control points in the first and last model of the strips 
are used for a linear strip adjustment. According to this procedure two strips of twenty- 
nine models were adjusted (flying height above ground 5400 m, ground elevation differ- 
ences up to 1300 m, Stereoplanigraph C-8, length of the strips 84 km). On the basis of 56 
and 54 test points respectively the following standard residual elevation errors were 
obtained: 
Strip1: m, : 3.8 m 
  
Average + 3.3 m 
Strip2: m, = + 28 m 
The same adjustment procedure was applied to two shorter strips of eleven models, 
(flying height above ground 5400 m, high mountains, length of the strips 35 km, 16 test 
points). The standard residual elevation errors are: 
Strip 1: m, = + 2.4 m 
Average — 2.2 m 
Strip2: m, — + 1,9 m 
Dr. Brucklacher mentions that further information on the status of strip triangu- 
lation with auxiliary data in Germany can be obtained from his publication: ,,Zur ràum- 
lichen Aerotriangulation von Bildstreifen, 1959". With regard to the required time for 
strip triangulation with statoscope data, Dr. Brucklacher indicates three to four hours 
for setting up the first model and forty minutes for each following model. Twenty-five 
minutes per model is required to print the coordinates of about fifteen points per model. 
Dr. Brucklacher states that the aerolevelling method is less expensive than the aero- 
polygon method, since less ground control points are required when compared with the 
aeropolygon method.