nsa activities. The 
raph is given as 9 
lative orientation, 
; 30 minutes. This 
) map. This point 
rs for a 1 : 50,000 
composed of 620 
of control obser- 
otting, 2000 days 
:10,000 for maps 
ne (0.06 of mile), 
data on produc- 
5, the larger part 
it 1:10,000 with 
quare kilometer. 
0,000. 
|. information on 
interval 10 feet; 
| : 5,000; stereos- 
, Camera 6" T5. 
Stereoplanigraph 
0 man hours — 
ile (2.6 km?) 34 
ows: Air photo- 
aphy, 3%; Field 
-paratory opera- 
f multiplex plot 
nization reports 
900 km? for the 
hotogrammetric 
costs. 
end of 1951 at 
87,400 km? at 
[GM since 1948 
(363) 
and revision of about 1500 km? of the Dolomite region by terrestrial photo- 
grammetry. The time for plotting one section of the 1 : 25,000 (95 to 100 km?) 
in average terrain is 2 or 2'/ months per machine working double shift 14 
hours per day, plotting at 1 : 20,000. 
At the Cadastral Service, the Nistri Photocartographe gives a monthly 
production of 500 to 600 hectares (2—2'/5 sq. mile). 
The cost of producing a sheet at 1 : 25,000 1s given in mounths per operator 
for photogrammetric surveys; on the ground 2 months, 3 months for plotting, 
total 5 months (1 operator and 2 helpers). 
In France at the IGN only some average production figures are cited: 
1 : 20,000 map of France, 1 shift of 1 operator and 1 draftsman, 20 to 25 hec- 
tares (0.08 to 0.10 sq. miles) per hour 1:50,000 North Africa, 1 operator only, 
60 hectares per hour; 1 : 100,000 territories 1 operator only, 2 km° to 4 km” 
per hour. 
For the 1 : 20,000 map of France the percentage costs of the different oper- 
ations to the total costs are approximately as follows: 
Air Photography 10%; Ground Control 25%; Plotting and Compilation 
30%; Field completion 35%. 
VII. Miscellaneous Questions. 
Few national reports contained information under this heading. The 
American report mentioned the construction of the “Twinplex” plotter for 
photographs from twin mounted aerial cameras which permits plotting mo- 
dels of double photographs inclined 20 degrees in opposite directions from the 
vertical and oriented perpendiculary or parallel to the flight line. Also men- 
tioned is a new model of the Kelsh Plotter of which many are actually in ser- 
vice. 
The German report cites theoretical researches in rectification. R. Bruck- 
hardt has set up approximate formulas valid to 20° of inclination. Other 
research treats of the determination of the air station from the elements read 
on the apparatus once the rectification has been made. C. A. Franke and 
Schwidefsky studied formules for transformation of the images in rectifying 
apparatus; these procedures permitting the projection of a map in a system of 
projection other than that in which it was made. 
The same report mentions the work of R. Finsterwalder on the precision 
of orientation in reference to the theory of errors and the extension of this 
research to rough ground. On returning thus to problems of the determination 
by remeasurement of the air station in space, we come closer to reality accord- 
ing to the author of the report. 
Mentioned also are studies of orientation of models and strips of photo- 
graphs by analytic methods including studies on the indeterminate conditions 
of the stereoscopic images (critical surfaces). Also cited are studies of atmos- 
pheric refraction, on multiplex by ordinary anaglyphes and polarizing filters, 
etes 
The Austrian report listed the state of numerous studies. H. Schmid, 
following the theory of errors, calculated for a grid of known points of unlim- 
ited number and regular distribution, the mean errors of the elements of 
orientation, (distribution of residual parallaxes). J. Krames starting from his 
"theory of critical surfaces," produced a new graphic procedure for relative