XIII
photogrammetric survey of the internal bearing structures of the
Dome of S. Maria del Fiore in Florence and the static control of
Palazzo della Ragione in Padua were presented. The
contributions showed that digital photogrammetry offers good
methods for architectural surveying.
In the next four days of the meeting, other technical sessions
have followed. The great number of presented papers could not
be reported in details. Some general remarks on presentations
and some highlights will be given therefore. However all the
invited, presented poster and papers will be published in the
I APRS.
The participants of the meeting learned of the increasing use of
WEB in these disciplines. Data transfer, GIS applications, 3D
models, etc. can be handled and spread out via Internet.
Applications of high interest were done on the cultural heritage
architecture. A new automatic, soft classification method for
estimation of the blanket of snow, by remote sensing, and
mapping of hydro - thermal alteration, by the same techniques,
were reported.
Further on, some theoretical considerations on metrology and
data processing were presented. A scientist, being the last Ph.D.
student of Prof. Mariano Cunietti, went deeply into some
concepts of epistemology and linguistics related to metrology
(the problem of uncertainty was especially taken into account).
An attempt to built up a synthesis, in the field of pattern
recognition, showed some contributions, coming both form the
linguistics and the AI. Regarding applications, a comparison
between a classical geoid and its determination, via GPS, was
presented. Moreover a software for georeferencing of digital
images by using plane transformations (GeoPlanTran),
developed by students, was also demonstrated, as a practical
application of digital photogrammetry.
Great achievement of different partners from research centers
and from industry, working on the fully Italian mission of
mapping from space, regarding satellite accelerometry - SAGE,
was presented. There were a lot of organizational and
professional problems, but the team whose pilot center was at
the TU of Milan, under the leadership of Prof. F. Sansd,
succeeded to finish the first part of the project, in only one year.
More information are available on the WEB - site, via internet,
http://ipmtfl4.topo.polimi.it/~sage.
Furthermore a new extraterrestrial mapping, in the framework
of the project - GAIA, was presented. The goal of the project is
to upgrade the existing star catalogues, by providing a precision
catalogue of one billion stars, using high resolution
measurements with micro - arc second astrometry from space.
The use of an automatic DEM generation in quarries, the
establishment of a precise leveling network, for the monitoring
of possible vertical movements in Pisa and in its surrounded
area, and some surveying methodologies suitably applied in
volcanic regions, like the Phlegrean district (near to Naples),
are interesting topics, presented in the field of deformation
monitoring.
Prof. K. Kraus lectured a current topic, namely «Determination
of terrain models in wooded areas with airborne laser scanner
data». Airborne laser scanners for recording topographic data
are ready to be used in various applications. He reported on
experiences acquired during the pilot project, comparing
photogrammetry with laser scanning from the user’s point of
view. Laser scanning is the dynamic method of data acquisition,
with laser rays from airborne, and is especially suitable for
measurements, to obtain terrain models in wooded areas. It is
necessary, to use GPS and INS during the laser scanning, in
order to be able to define the position of ray origins. Thus the
geoid undulations of the area are required.
Laser scanning supplies data with a skew distribution of errors,
because a portion of the supplied points is not on the terrain,
but on the treetops. Thus the usual interpolation and filtering
has to be adapted to this new data type. He reported on the
implementation of this new method which bases on linear
prediction algorithm and works iteratively, taking into account
robust estimators. He concluded that laser scanner data provide
DTM’s, in wooded areas, with an accuracy equivalent to
photogrammetry DTM’s, in open areas, derived from wide-
angle images of scale 1 : 7000. In flat terrain, the accuracy is + /
- 25 cm. After further improvements in the data processing, an
accuracy of + / - 10 cm can be achieved for laser DTM’s. With
a special filtering and interpolation method, an automatic
classification of the laser points, into terrain and vegetation
points, is possible.
The participants heard also of the use of GPS, GLONASS and
other systems used for real - time positioning in Italy. A
historical overview was given by Prof. G. Manzoni. Prof. F.
Sanso added some comments on the current state in this field in
Italy. Big powerful industrial firms are prepared to invest for
establishing more permanent GPS stations in Italy. However
not only money is needed, but also proper professional
solutions must be considered as well.
The two last technical sessions dealt with digital
photogrammetry and it’s usage for camera calibration,
restoration purposes, architectural photogrammetry, historical
studies (an ancient perspective in Lecco has been analyzed and
matched with a new survey). In this frame, biologists showed
the first results, concerning a special type of image processing,
of the participation in the gene functional mapping project.
The business session was chaired by the ISPRS VI/3 Co - chair
- person. Firstly a short overview of the working group
activities was given by Chair - person. The working group has
around 280 members, between participants and correspondent
members, involving 46 countries (around the half of the ISPRS
ordinary members). Consequentially one can say all the
meetings (Padua (Italy), February 3-7, 1997; Bahia Blanca
(Argentina), October 27-31, 1997 and Perugia (Italy), February,
16-20, 1998) have been a full success.
Successively it was pointed out that an official meeting was
originally scheduled, in the first week of February, at the
University of Cape Town (South Africa). This meeting in Italy
(Parma) would represent a repetition, because the two places are
far enough. Unfortunately, unpredictable and undesirable
difficulties and troubles in Indonesia imposed a delay of one
year, the ISPRS TC VI Mid Term Symposium.The ISPRS
Council canceled the Meeting in Cape Town, because of an
evident conflict of date. However the ISPRS WG VI/3 staff
obtained a new official meeting to be held, in the second week
of December 1999, in Cotonou (Benin, Africa).
