The optical interchange of the pictures makes it easy to connect consecutive pictures 
through the alternating use of “base inside” and “base outside”, also to plot from 
individual models since the time needed for insertion of the frame and absolute orien- 
tation is considerably reduced. 
The great versatility of the optics will no doubt have a very favorable effect on the 
efficiency of strip radial triangulation. The AT is specially designed for several methods 
of aerotriangulation, since it can be expected that this technique will be more used in 
the future than it has been in the past. 
All orientation elements and all controls can be set from the operator’s seat. The X 
and the Y carriages can be moved freely during orientation as before. 
An automatic shifting device for all desired transmission ratios between the autograph 
and drafting table gives direct reading in meters and feet on the altitude counters, for 
all usual scales. 
Large counters make for convenient reading of the coordinates and orientation ele- 
ments. 
An auxiliary transmission, provided on request, also gives scales or representative 
fractions such as 1:1,200, 2,400, 4,800, and 6,000, as well as 1 inch — 1 mile, &c., with 
the meter or feet readings on the altitude counters. 
As regards the drafting table, we only want to mention that, by the attachment of a 
second tracing point carriage, the connecting areas between adjacent sheets may be 
mapped simultaneously in any position of the sheet. 
An additional mechanism in the AT, for the point by point determination of machine 
coordinates, in the future, will be an electrical coordinate recording mechanism. 
However, this recording mechanism will be installed only on special request, since its 
value is limited to relatively rare uses having to do with the recording of boundary 
points in cadastral surveying. 
Finally, we stress once more the greater universality of this machine with respect to 
that of the A5, due to the increase in the plate size. Photographs in all sizes up to 
23 x 23 em (9”) can now be plotted from, for all focal distances from 98 to 217 mm, 
while possible distortion caused by the objectives can again be eliminated by means 
of the time-tested optical compensation plates, in a simple and reliable manner. 
However, an efficient photogrammetric organization equipped with precision instru- 
ments alone can no longer be considered complete. Part of the functions must be taken 
over by simpler mapping equipment. 
The combination of the A5 Autograph and A6 Stereoplotter has proven satisfactory 
in practice everywhere, particularly now that the precision of the A6 has been 
brought to its present level by various construction refinements and improvements 
in the manufacturing processes. 
Thus, the A7 also needs to be completed by a less expensive mapping machine, 
similar to the A6. Of late, the A6 has been used more and more successfully for 
mapping at a scale of 1:5,000. 
When it still was necessary to use representative fractions between 1:8,000 and 
1:10,000, the A6 proved capable of doing the job, although actually designed for 
representative fractions of 1:10 000 or less. 
However, the improvement of the photographic optics by development of the Aviotar 
and Aviogon lenses brought about the fact that the flights could be made at higher 
altitudes and, therefore, be carried out more economically, without any loss of pre-