NORWAY 
11 
REPORT FROM THE FOREST SURVEY, 
MINISTRY OF AGRICULTURE 
Forestry. 
The purpose of the National Forest Survey of Norway is survey and 
mapping of the forest-land that is administered by the Ministry of Agriculture 
and that constitutes about 14 % of the total forest-land in the country. The 
extent of the separate forest areas varies from a few to over 50.000 hectares. 
Many of the areas are situated at considerable height and include extensive 
grounds of bare rock. 
For the more extensive forest tracts the map scale usually is 1/10.000 
with contour interval 10 m., for the smaller ones 1/5.000 and with contour 
interval 5 m. Maps for special purposes are prepared at scales up to 1/1000. 
The maps are intended to cover the need herefore in management, in border 
questions, to serve as a basis for sub-divisions etc. in the management, and 
to meet the administration’s need of a general survey of the forest-lands. 
The use of aerial photography has been introduced in 1948, and today 
it plays an important part in map-compilation. The use of vertical photographs 
has been combined with the necessary field work for the timber survey. Up 
to the present only the simplest methods and means have been employed. 
The work has been carried out as ordinary timber line survey. Photo 
interpretation, passpoint determination, and the marking of contour lines are 
all included in the ground survey work. Contour lines are marked directly 
onto the stereoscopic model during the work in the field by means of a re 
cording barometer and with support in trigonometrically determined vertical 
control points, such as lakes, mountain peaks etc. At the same time boundaries 
for forestal data for interest are marked on the photographs. 
Roughly determined horizontal control points are also provided by mea 
surement of timber lines with tape measure. At even intervals characteristic 
details on or near the timber line are marked onto the photographs and the 
measured distances noted. The line distance has been 4—500 m. Distance 
between the points along the line depends on the roughness of the ground and 
varies between about 300 m. and 1000 m. 
The terminal points of the timber lines, all marks denoting property 
boundaries, and a few other important details are measured trigonometrically 
by triangulation and traverse. The control point distance in triangulation has 
been one triangle point per 3—7 km 2 . 
Triangle nets, line nets, passpoint nets etc. are later construed on the 
map cardboard. The transfer of details from the photographic material to the 
maps is made by fitting in the prints to the passpoint marks, and up to the 
present it has been made with quite simple apparatures, such as Zeiss Bild- 
umzeichner and a Vertical Projector. 
In spite of the primitive methods and aids considerable results have been 
obtained in the form of increase of capacity and reduction of expenses. Spe 
cial studies of the accuracy of the proedure have not yet been made. However, 
it seems fully satisfatory to the purpose. 
The method has specially been applied to continuous extensive forest 
tracts that offer the technical advantage of considerable increase of the line 
distance (from earlier max. 200 m. to now 500 m.) 
Photography has been at a scale of 1/15.000 with Kamera Wild RC5,