Detailing is done chiefly on the A-8. The Power Board does not own
an A-8, but has placed the work with private engineering firms and
with the Service Department of the Geographical Survey Office.
The Nordkalott project
The Nordkalott project might be called a synthesis of the experience
the Power Board has had in the application of geodetic surveying and
photogrammetric procedures to reconnaissance and planning in the
development of hydroelectric power resources. The mission is to exploit
the power resources of the Torne and Kalix rivers and of other Vnd
and rivers in the same part of the country.
My remarks concern only the work in the northeastern part of this
area.
When the regions of importance to the project had been entered on
the topographical map, strip photographs to be taken at 6.000 meters or
higher were planned, and work on the establishment of the ground net
was begun. Fig. 3 shows this net as it appeared in 1958. More data have
been entered since. The net was developed by a combination of triang-
ulation and telluro-metric measurements. During the summer of 1958,
more than 120 stations were surveyed by two men. This included recon-
naissance, marking the stations for photogrammetry, and vertical tri-
angulation. The party travelled by helicopter.
Fig. 4 shows the area surveyed, the accuracy, the time required, and
the costs. Computation and the entering of data are not included in the
cost figures.
When the photographs were ready, the small-scale mapping was
started. The procedures were in the main as described previously.
The small-scale maps were used to determine where low-altitude
photographs would be required, Stereoscopis studies combined with
photogrammetric triangulation were also used. This procedure, applied
as early as 1955 in location studies for Power Board road projects,
often saves both time and money. An engineer and a photo-
grammetricist work together with a Kelsh plotter or a Balplex. Eleva-
tion is studied at doubtful points and impracticable proposals are dis-
carded. This saves unnecessary mapping.
For regions where detail studies are required, strips at lower altitudes
(usually 1200 to 1500 metres and 2300 metres) are ordered. In these
regions, the base network was supplemented with tellurometric pique
points (spaced at 2 to 3 km intervals). Between these points conventio-
nal polygon chains were run, with reconnaissance and marking of sta-
tions for aerial photography. These chains were for use in the orienta-
tion of objects of interest. The coordinates of the stations in the chains
of polygons were obtained by photogrammetric triangulation. At this
stage of the project, the precision obtained by this means (0,5 to 1,0
