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Later, the map was printed at a scale of 1:20 000, and for
the moment printing has ceased in favour of a "Forced
Database Edifice". In order to render the production more
effective and to minimize field work, analytical
photogrammetric instruments of the type Zeiss
Planicomp P3 or Casco-modified Wild B8 are used for
data collection.
3.4 Digital Photogrammetry
In 1994 the NLS decided to accomplish a study of digital
photogrammetric workstations. The main objective was
to enable production and mosaicing of digital
orthophotos. Other objectives were automatic production
of digital elevation models, acquisition of vector data for
mapping and map revision, especially updating of the
Economic Map database, and good basic orientation,
measurement and triangulation capabilities.
The decision was made to purchase a complete digital
photogrammetric system from Leica/Helava, consisting of
a DSW200 Digital Scanning Workstation and five digital
photogrammetric workstations — one DPW670
monoscopic station and four DPW770 stereoscopic
stations. The system is used mainly for production of
digital orthophotos. Special products including digital
orthophotos, elevation models and image map plots for
road design have been produced for the National Swedish
Road Administration. Tests have been made of the
automated triangulation software module HATS (Helava
Automated Triangulation System), which is approaching
sufficient stability to be used in production.
For data collection and updating of the Economic Map
database, two Zeiss PHODIS ST with PHOCUS software
were purchased. Stereoscopic superimposition of map
data and use of PHOCUS mapping software has shown
great potential for its purpose.
4. THE NATIONAL SWEDISH ROAD
ADMINISTRATION
After an inventory phase the first digital photogrammetric
workstation in Sweden was delivered by Intergraph to the
National Swedish Road Administration in January 1994.
It is of the type ImageStation. The main purpose was to
provide road designers with orthophoto maps and digital
elevation models as a base for early design phases.
The workstation is connected to a network including
analytical photogrammetric instruments of the type
System 9. In 1995 the system has been completed with
another ImageStation.
Plans are to develop products for visual presentation of
road design projects.
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B6. Vienna 1996
5. PRIVATE PHOTOGRAMMETRY
CONSULTANTS
5.1 Structure of Companies
Swedish private photogrammetric consultancy has faced a
radical structural rationalization due to increased
competition in the period 1992 - 1996. Today there are
five relatively large consulting firms in Sweden, as well
as a number of minor firms. The larger firms together
employ some 100 persons in photogrammetric
production. :
5.2 Resources
There are no Swedish private companies offering aerial
photography for mapping purposes, but Swedish
companies co-operate with Danish and Finnish
companies with aerial photography resources.
Swedish photogrammetric companies have approximately
35 stereo instruments in total. Among these there are 15
analytical instruments. Almost all mapping today is
digital. The analog instruments are in general modified to
accomodate digital mapping. Most of the instruments are
connected a CAD- or GIS- system for data capture and
editing of map data. Datafiles are delivered in a common
Swedish data format (KF85) for exchange of digital map
data.
Digital photogrammetry has not yet been introduced on a
permanent basis among Swedish consulting firms for
photogrammetric production.
5.3 Customers and Products
Sweden has been facing a difficult economic situation
during the last years. This has caused major cut downs in
public expenses, especially within municipalities,
resulting in reduced planning and building activities.
Therefore, local map production has slown down, and
investments in GIS systems have dropped. The
conversion of analog maps into digital map data, as well
as production of new digital map data is far less than in
earlier years.
On the other hand public investments for infrastructure
have increased considerably. The National Swedish Road
Administration and The National Swedish Railway
Administration are performing major projects in road and
railway design and construction. The need for
photogrammetric products have consequently adjusted to
that situation. Photogrammetric digital map data and
digital terrain models for infrastructural project design are
today the main products.
There is also an increased interest in orthophotos for
preliminary design of infrastructural projects. This is
expected to promote the introduction of digital
photogrammetry.
