difficulties in absolute orientation. 
In photogrammetric analog instruments the ranges 
for tilt, inclination and base components as well 
as the model ranges, above all the ranges of 9, uw, 
bx, by, bz and of course the Z-range are often too 
small for the adjustment of terrestrial parameters. 
Also in this respect it is obvious that the numer- 
ous limitations can only be overcome by using an 
analytical stereoplotting system. 
2.5 Output of data and data processing 
Relating to the output of data there are also 
existing some differences between the topographi- 
cal and non-topographical application. While in 
the topographical evaluation of aerial photographs 
the result is represented either by planimetry 
mapping with contour lines or by digital output of 
coordinates (triangulation data or digital terrain 
models), there are a lot of special cases and addi- 
tional clients! requests in the non-topographical 
field. So, normally a both graphical and numerical 
output is necessary. In many cases also horizontal 
or spatial distances, angles, areas, volumes or 
centres of gravity like values derived from coor- 
dinates are of interest. Surveying objects 
variable in time (movements, deformations) mostly 
an immediate comparison of coordinates (before and 
after movement, respectively between nominal and 
actual values) is desired. This direct comparison 
is only possible in analytical systems. A great 
support for locating the model points in the com- 
parison process is the automatic positioning of 
single points or grid points. 
A further problem (mainly occuring in the non- 
topographical photogrammetry) is the graphical re- 
presentation in oblique planes and perspectives as 
well as in unusual projections. Of great impor- 
tance are unwindings of surfaces not only for 
architectural application but also for industrial 
survey. This type of representation can be 
generated with an analytical system in the on-line- 
mode, i. e. in quasi-real-time. 
2.4 Conclusions for the choice of a restitution 
system 
The list of peculiarities demonstrates that aero- 
photogrammetric analog instruments don't comply 
with most of the specifications of non-topographi- 
cal photogrammetry. Some of the problems being 
mentioned can be solved by analytical off-line 
restitution, i. e, by digitizing of the objects' 
data. The off-line method, however, is mainly 
efficient for the evaluation of single points. For 
graphical representations in planes and sections 
the off-line method is not possible because with- 
out orientation during the measurements there is 
no reference to the planes and projections to be 
mapped, 
Analytical on-line restitution seems to be more 
appropriate, because the results are immediately 
available and can be checked and estimated at once 
in regard of completeness, accuracy and statisti- 
cal evidence. Completion, modification and repe- 
tition of measurements are easily possible. 
Due to the comprehensive software and easy oper- 
ation the ZEISS Planicomp analytical system seems 
to be exceptionally predestinated to non-topo- 
graphical work. In the following a general des- 
cription of the instrument as well as references 
to special service programs are given. 
98 
3e Description of the ZEISS PLANICOMP C 100 
The analytical stereoplotting system PLANICOMP 
C 100 (fig. 1) consists of the hardware-components: 
- basic opto-mechanical unit 
- photogrammetric control panel 
- electronic control unit 
= minicomputer HP 21 MX 
- terminal, printer 
- digital tracing table DZ 6 
Some of these components are described in the fol- 
lowing passages. 
  
Fig. 1: Planicomp C 100 with HP 21 MX mini- 
computer, video display and line printer 
5.1 The basic opto-mechanical unit 
The opto-mechanical unit is more or less in confor- 
mity with a stereocomparator, but with the 
difference that the images are driven by the com- 
puter. The instrument contains two separate servo- 
driven systems of photo carriages moving in x and 
y and a fixed optical unit for viewing. As 
floating mark either a selective reversible black 
point can be used or a luminous mark with variable 
intensity and of 40 um or 20 um diameter. By a 
prism-control unit the choice between orthoscopic/ 
pseudoscopic and binocular monoscopic viewing of 
the left-hand and right-hand photo is possible. 
Slip-on eyepieces for 8 x or 16 x viewing magnifi- 
cation are on disposal. 
5.2 The photogrammetric control panel 
The control panel allows perfect control and 
checking of practically all operations required 
for orientation as well as for numerical and 
graphical evaluation. The fictitious model is 
controlled by the two handwheels with high and 
low gears and foot disk. A free-handed motion is 
possible by using a joystick acting in a non- 
linear way. Regarding the movement of the floating 
mark there can be selected between normal model 
Scanning, terrestrial evaluation and profile 
scanning. 
The control panel disposes of an eight-digit 
coordinate display for either photo-coordinates 
xy y'y x", y", model coordinates x, y, z or 
ground coordinates X,Y,Z. Of importance for the 
program control are the decision keys "Continue/ 
Yes/Start", "Repeat/No/Stop" and "Execute" as well 
as the indicators for program status "Busy",