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In the Hungarian practice of examining tall
buildings for displacements, generally base
line relations of 1/2 or 1/1,5 are appljed,
providing for intersection angles of 28 or
3T , concomitant overlaps being 40 to 25 %
for horizontal, and 60 to 50 % for vertical
pictures (f = 195 and 100 mm, respectively).
These base line relations provide for a de-
termination confidence for "y" equaling those
for "x" and "z",
Building surveys apply base line relations of
1/3 accompanied by 19 intersection angles
and 60 to 70 4 overlapping.
Problems of terrain survey character are pos-
sibly made with base line rglationg of 1/10
to 1/4, corresponding to 6 to 14 intersec-
tion angles and 70 % to 85 % overlapping. Of
course, relevant "E" values vs, base line re—
lation will be 1/13000 or 1/6500, in the best
case, and 1/2000 or 1/1000. in the worst case,
depending on the camera type.
we did a bit of meandering in the subject of
terrestrial photogrammetry. For the sake of
completeness let us have a look at the per-
formance of aerial photogrammetry, According
to observations, below a flight of 1000 m re-—
lative height, spatial co-ordinates (if pro—
perly adjusted) involve an uncertainty of +3
to 4 cm, growing gradually to + 10 cm between
1000 m and 2000 m height, In aerial photogram— -
metry, the base line relation is generally
1/1 or 1/2, hence favourable,
As seen by the fields of application, indus-
trial photogrammetry is mostly terrestrial in
Hungary. 90 4 of our terrestrial photogram-
metry instruments for recording are photo-
theodolites and rigid—base measurement cameras
of the Zeiss factory in Jena, Also much of
our evaluating instruments are originated
from here, including comparators, stereometers,
monocomparators,technocharts, stereometrographs
topocharts and we also have a series of Wild
instruments such as As s Ags Bg etc,
without striving to completeness, in theo-
retical and practical problems, the following
gources of error in taking shots were encoun-
tered:
— deficient knowledge of the phototheodolite
main point eccentricity;
— missing method for eliminating bearing er
rors;
— deflection error in some direction due to
incertainties of sighting extension refe-
rence piece or sighting;
— distorsion of UMK cassette holders causing
deficient verticalness of the plate;
— missing exposure of UMK frame signals;
— missing determination of ihe variable aber-
ration values of UMK in different conditions
of photographing;
— insufficient immobility of the camera in
time-base shots;
— glight possibility of exact determination of
outer orientation elements,
Remarks on evaluations
— monochromous, extended surfaces are uncer—
tain to evaluate;
- measuring marks of the evaluating instruments
are multiples of the magnitude to be measured.
Bb. General problems and remarks
Further development of industrial photogram—
metry is inhibited by the uncertainty of ba-
sic material supply, In the last two years,
no glass negatives could be obtained in the
quantity needed, forcing us to use films stuck
on laminated glass plates, These materials are,
however, prone to distorsion, multiplying the
sources of error in a rather adverse manner,
Another problem is the impossibility of ap-
plying colour technique because of basic ma-
terial shortage.
The correlation between the photogrammetric
data bulk and the geodesy system often dis-
torts homogenity.
I must apologize for this rather capricious
train of thoughts but clearly, it is not a
simple problem to have industrial photogram-
metry "well done",
Last but not least, let me remark that ap-
proach to literature would have required
mentioning bio-photo;rammetry, astronomic ob-
servations and casualty photogrammetry. These
fields of application do exist in Hungary,
though at an experimental stage. Let me drop
now some words on the expected trends of de-
velopment, Industrial photogrammetry is felt
to have wide perspectives provided the mul
tiplicity of technical and engineering inhi-
bitions can be eliminated, and many spe-
cialists convinced and have their minds
changed in order to make a valuable work
tool of this method,
Thank you,
