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Thus we use different methods of data collection:
1. Aerial photographs. scale 1:3 300, colour-diapositive film, with signalized control
points.
2. Digitizing of existing maps.
J. Terrestrial surveys.
The photos are used - for aerial triangulation as geometric basis of an updated cadastral
system as reference for all other data: : :
- for connection and updating of cadastral and utility data:
- for information about traffic and topographic situation.
The adequate method of data collection depends on the facts: effectiveness and accura-
cy. All collected data are revised by an inter-active graphical system.
3. Utilized hard- and software components
The basic modul for all calculating programs and for the communication between all
utilized instruments for the input-output is a microcomputer PDP 11/23 of the Digital
Equipment Corporation (DEC) (see fig. 1.5) It is operating with the RT-11 runtime
system and a 258 kbyte memory is available. Programs and data are stored on a 20 Mbyte
winchester disk: a floppy disk unit is used for the transfer of external data.
For the establishment of a LIS of the project Neustadt, the following data are available:
diapositiv aerial photographs in the scale !:3 300, already existing maps in the scale
1:1 000 up to 1:500 and several terrestrial surveyings.
The measurements made in the aerial photographs will be the geometrical fundamentals
for further informations. The ground coordinate system is the local one of the Federal
Republic of germany, based on a transversal Mercator projection.
To get more control points and to figure out the coordinates of the excentric located sig-
nals the electronic theodolite Kern E2 with the electrooptical distance meter OM 502
and the memory unit RUB is applied (see fig. 1.3). The registered data are adjusted with
the program GEO 100.
The photogrammetric measurements were carried out on the Kern DSR-1 (see fig.1.1) This
analytical plotter has a consequently structured module architecture of hard- and soft-
ware (see Klaver, Stampa-WeBel). Those programs. all working with the menu-technique,
may be combined by the user as it is necessary for the project.
Ground control points are the geometrical base of the photagrammetric work. For con-
trol densification and for the improvement of the cadastral survey net a block adjust-
ment was necessary. The required accuracy level could only be reached by bundle block
adjustment. The measurement of the photo coordinates was done with a standard pro-
gram from Kern on the DSR I.
During measurements and calculations. existing additional information like the camera
calibration, control points and segments of cadastral coordinates can be added (see fig.1.4
and 1.8). -
For getting a higher reliability and also better accuracy the block was measured with
80 75 endlap.
Without loss of time for data transfer, the bundle block adjustment was made on the
PDP 11/23 of the DSR! with the Hannover program system for bundle block adjustment
BLUH. The computation of the block with 59 photos took 33 minutes per iteration.
Even with the robust estimators, included in BLUH, no blunder was detected in the data
set, because of the online check during measurement. The standard deviation of unit
weight, sigma 0 of 4.5 microns corresponds to an object accuracy in X and Y of approxi-
mately £ 1.0 cr, Each object point was measured in the mean in 5.8 photos. Thus a good
reliability was achieved. Together with the object accuracy this is sufficient even for
the geometric improvement of the cadastre.
