Jhg.-v. Dez. 1948.
Fluh and Buch in
;ale of 1:8.000 for
- »Das Luftbild als
1947, No. 23/24, p.
emeine Forst. und
1948). These data
estionnaire.
.000 is required
own, 60 cm for
n a satisfactory
ey of 1935 with
nhof near Neu-
it must be con-
is too small for
inology of the
height diameter
:1idth. — crown-
er, volume- and
mination of site
site is made on
| will be about
rough the Board
reliminary base
me size. It must
photographs, an
hotographs, the
ased. Industries,
en smaller map-
4000 or 1 : 8000,
which are recti-
al picture sheets
district. In the
ectified pictures,
1 to the scale of
ing in Lapland.
outh of Finland
ra on a scale of
00. The pictures
were studied in
19
The surveying executed by different firms and forestry committees was
made on different material, but simple pictures with large scales were
generally used.
(c) A thorough field interpretation was made with a few exceptions. In
the sitework the site boundaries are drawn on the photograph and through
measurements of areas, directly on the picture, the site division of the
region in question is obtained. In the survey work of the Board of Forestry
stereoscopic pictures are used. The enlarged pictures, 36 7X 36 cm, are cut
in three, and the three parts are fastened together to form stereoscopic
pictures on a piece of cardboard. The stand is investigated from the ground
and the stand boundaries are directly drawn on to these photograps. The
stereoscopic pictures are then undone and fastened together so that the
original enlarged picture is obtained, but now with the middle part made
more clear by the stand boundaries drawn on to it. These boundaries are
directly copied on transparent material, on which pass- and control-points
are drawn. These points are of course also drawn on tc the picture.
The controls and pass-points were at first constructed by graphical radial
triangulation, but since 1950 the slotted template method is used.
In 1951 a forest map of an area of about 10.000 hectares, scale 1 : 20.000,
was compiled in 10 days at the Board cf Forestry. It was used for the
planning of a large cutting area in Northern Finland as well as for logging
from this area.
The work was executed as plain indoor work, based on aerial pictures,
an old map of stand, scale 1 : 50.000, and a description belonging to this
map. We have not yet received a report cf the fitness for use of this map,
but it is obvious that the new map surpasses the old one considerably.
(d) There is no exact information about the accuracy of the mapping.
Generally it can be said that maps based on aerial photographs have been
approved by foresters.
(e) Approximate calculations show that mapping based on aerial photo-
graphs is about 50 per cent cheaper than those made according to classical
methods. These calculations were made by the Board of Forestry.
(f) Aerial pictures were not used in forestry before the war, but nowa-
days all forestry mapping projects of importance seem impossible without
them. The mapping, which was quite dead during the war, is now very
active. It is therefore not very likely, that the activity will be more exten-
sive, but the aerial pictures will probably retain their importance in the
future development. It is possible that the photographs will find a wider
employment in the future.
France:
Photogrammetry is for the present very little used for forestry purposes
in France. The plans of the State forests were drawn up long ago and
aerial photographs only serve to revise these plans. However, photogram-
metry is used in forestry for some special purposes stated below under
question 3, 4 and 8.