these private companies rent the aircraft when need arises.
Since there are few ideal flying days per year this explains
why so many cameras are available in such a small country.
2.2 Activities of the Swiss private photogrammetrists
Private photogrammetric companies have contributed
substantially to accomplish large projects based on aerial
photography in the last four years. The collection of basic
geographic data on a national and a cantonal level was one
of the most important tasks. In conjunction with the
establishment of land information systems the layers of
surface coverage and digital terrain models were compiled
to meet the requirements of the Official Cadastral Survey
and of large construction projects.
One project worth mentioning is the determination of the
perimeter of the AlpTransit trajectory for the Swiss federal
railways. Also for the Swiss federal railways
photogrammetry made it possible to establish along all the
main railway lines a 3D model based on which a noise
impact cadastre was created.
The digital orthophoto has proven to be a innovative
product with a high potential for very diverse future
applications. For this purpose large aerial surveys where
carried out by various cities and cantons.
Photogrammetry has established itself firmly as the method
for forest health inventories and for basic flood control
mapping. The latter was carried out mainly by means of
helicopter-borne aerial photography.
Swiss private photogrammetric companies have also been
active abroad mainly to help establish cadastral information
systems (partly based on digital orthophotos) and to help
put into operation cartographic production lines.
3. PHOTOGRAMMETRIC INDUSTRY
3.1 Analytical and digital photogrammetry
Shortly before the ISPRS Congress in Kyoto 1988 a historic
change in the photogrammetric industry in Switzerland took
place: Wild Heerbrugg and Kern Aarau had been brought
together and the first digital stereoplotter DSP1 was shown
on the common booth.
In 1990 both companies were integrated into the LEICA
holding company together with 5 other high-tech
companies. A careful analysis of market and technology in
the field of Digital Photogrammetry led to a partnership
between Leica and Helava. The ISPRS Congress in
Washington (1992) was the appropriate occasion to
announce this partnership.
Between 1992 and 1996 Helava and Leica together have
established themselves as a provider of leading edge
technology in the field of digital photogrammetric
workstations and scanners.
78
3.2 Photogrammetric developments within Leica
Intense efforts continue to be invested in Leica's complete
range of photogrammetric product lines:
* RC30 / ASCOT aerial camera system
* SD2000 / 3000 line of analytical stereoplotters
* DVP entry level digital photogrammetric workstation
* HELAVA digital photogrammetric systems
* INFOCAM land information system
* Laser Tracker to digitise moving industrial objects
* Axyz a multi-sensor industrial 3D measuring SW
e V-STARS for digital industrial photogrammetry
The Helava line continues to evolve very rapidly. The
DSW200 scanner and the DPW670/770 are now available
on the Sun Ultra host workstation and not only on the
SPARCstation. The new Creator 3D graphics offers first
class stereoscopic viewing and many of the latest Indy and
Indigo workstations from Silicon graphics are also available.
The current release of SOCET SET, software for the DPWs
includes all around improvements such as HATS (Helava
Automated Triangulation System), image map production
with PostScript output, feature extraction with semi-
automated tools promising real advances in productivity.
The popular ATLAS and PRO600/MicroStation packages
for map compilation continue to improve and the latter is
supplemented by a new optional module, TerraModeler
from the Finnish company TerraSolid OY, for the
manipulation of digital terrain models.
On the SD line of analytical instruments the ORIMA
software is becoming established as the standard software
under Windows and customers throughout the world are
keen to upgrade earlier models of Kern, Wild and Leica
analytical plotters in order to gain the advantages of the
latest developments.
Version 6 of INFOCAM runs under the Solaris 2.x operating
system on Sun workstations and thus shares this platform
with the Helava line.
Aerial Visionics Systems
In 1993 Leica acquired Magnavox Navigation and
Positioning Systems. The complete integration of GPS
receivers into the aerial camera system allowed to reduce
the amount of ground control needed for aerotriangulation
even further. The first step was to incorporate GPS
navigation into the Leica RC30 aerial camera system
providing perfect flight planning and flight execution - the
ASCOT aerial survey control tool was born. The second
step was to integrate GPS phase measurements, GPS post
processing, aerotriangulation and bundle block adjustment
into a reliable data processing chain to determine precise
perspective centre co-ordinates. This Combined Block
Adjustment method (CBA) which only requires 2 single
frequency GPS receivers, one in the air and one on the
ground, gives the aircraft an unprecedented operating
radius of 500 km with resulting decimetre accuracies for the
perspective centres. Ground control can be reduced to four
full control points in the corners of the block.
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B6. Vienna 1996
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