The calibrated fiducial and reseau coordinates are used for automatical 
positioning of the floating mark. The orientation of the photo on photo 
carrier is defined by the location of the photo side information and 
for not centered photos by the approximate location of the principal 
point on the plate. So it is simple to use also the outer part of the 
Large Format Camera photos. The program takes care about the photo part 
which is located on the plate, that means, in the case of the Large 
Format Camera all fiducial and reseau marks located on the plate can be 
measured, even if a fiducial or reseau mark is visible only in one photo. 
In any case the fiducial and reseau marks are measured before the photo 
points and in reverse sequence after finishing the measurement of photo 
points. Usually the photo points are measured twice, after the first 
measurement a second measurement will follow in reverse sequence, but 
this is an option. The back measurement is very fast because the pointing 
can be done accurately by the instrument, but usual an offset of 50 um 
is used for the second measurement so that the operator has to make an 
independent pointing, which leads to the information of the pointing 
accuracy. 
There are different possibilities of approximate or exactly automatic 
pointing of photo points. 
After transformation to the fiducial marks, the photo coordinates can be 
corrected by earth curvature and refraction influence and radial symme- 
tric distortion. A reseau correction can be done off-line by program 
BLPRE. 
2. COMPUTER SUPPORTED POINTING 
Photo points can be pointed approximately by program B159 with known photo 
coordinates of both or one of the photos, based on known object coordina- 
tes (ground coordinates) and based on measurements in the neighboured 
strip. 
Known photo coordinates we can get from preliminary measurements, approxi- 
mate from digitizer or with known object coordinates and photo orienta- 
tions from program APROX. Object coordinates we can get from an adjust- 
ment of a premeasurement, the first results of a deformation analysis, 
digitized maps or other sources. B159 computes during data aquisation 
strip coordinates. If at least 2 points are measured in the overlapping 
area of strips, a computer supported pointing can be done with trans- 
formed coordinates of the neighboured strips. 
3. ON-LINE BLUNDER DETECTION 
The term "on-line" has to be specified more in detail. A realy on-line 
blunder detection implies a check immediately after registration of a 
photo point. Usually this is not necessary. It is sufficient, to have 
a check after finishing the registrations in a photo model when the 
photos are still on the carrier and remeasurements can be done at once. 
Also the second type of check is named as on-line. 
If any prevalue of the point location is available, the program B159 com- 
pares it with the registration on a chosen accuracy level. Blunders are 
instantly notified. After terminating the measurements of a photo model, 
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