1978 ISP COMMISSION V INTER-CONGRESS SYMPOSIUM - STOCKHOLM SWEDEN
Wednesday, August 16 - Applications and Cost-Fffectiveness 7
Konecny: If you just minimize the v's essentially it amounts to some kind
of a shift. But what you probably meant is that you had some kind of mini-
mization of v plus another mathematical model for deformation, as I believe
was Prof. Torlegärd's suggestion.
Torlegärd: I would like to stress also Mr. Kenefick's conclusion that a
homogeneous accuracy is of the greatest importance for a successful result.
Newton: I would just like to comment on the work that I did in this field.
This was included in an invited paper in Helsinki. A similar technique has
been used as routine on two supertankers built in the United Kingdom , at
Clyde in Scotland. We got discrepancies between the two mating faces in
the order of about 30 mm maximum, but this did not seem to create any prob-
lems in the joining operations, when the thickness of the shell plate is
between 25 and 30 mm. The ship is so flexible that they are able to jack
out the shape to fit.
Miller: Is it practical and efficient to take the photographs with a very
good camera like the WILD P 3l, by hand? I think it would be a little:
difficult to determine the scale. What was the reason for taking the
photographs by hand on the bottom?
Karara: For convenience.
Miller: But you have three camera stations.
(There were many people talking at the same time here and
nothing on the tapes could be understood)
Konecny: I think that is the principle of aerial photogranmetry actually.
Where you want the information is on the object. Where the camera stations
are doen't make any difference.
Grün: I was glad to see that Mr. Kenefick used more than two images in
order to obtain a good accuracy and a good reliability, as I pointed out
in my paper. Then the question whether a usual bundle adjustment or the
use of fixed camera stations is not of so great importance.
GR S Se S RAUS SESS Sota ale rini ism arr
Paper by J. Sima - Research Institute of Geodesy - Prague
"PHOTOGRAMMETRIC MEASUREMENTS IN THE PRAGUE METRO"
. + * . - - - * . > e . * - * * . Ld . * + LÀ *. + - * - . > * LU . LÀ * * LA *
Konecny: You have on your slides shown that there are fifteen stereopairs
that have been measured. How many cross sections?
Sima: It depends on the task. If it is for traffic safety there will be
à cross section every 5 meters. But if the task is to compare the actual
state of the tunnel with the project requirements we check each meter of
the tunnel, so that there are eleven Cross sections in one stereopair or
10 meters of length of tunnel.
Konecny: And how often are these measurements made? And what are the geo-
logical conditions which cause deformations of the tunnels?
Sima: For traffic safety this is done after three months and tben after six
months and then each year. In Prague the Metro is constructed under very
strict safety regulations and the diameter of the tunnel is critical, the
distance between the tunnel wall and the trains being 10-15 cm or less.
