Sweden 15 
but slightly — are relatively extensively checked and adjusted in the 
field. By this check the contours are as a rule searched in the field and 
plotted on dectified pictures. 
By plotting the opposite shores of broad lakes the contours are also 
drawn directly on rectified pictures, because the water surface cannot 
be used as a vertical support for the stereoscopic work. 
In addition it may be mentioned that mosaics of various types are 
largely used for a great many purposes, and that photo-maps, based on 
control points fixed by aerial triangulation in Multiplex, are being in 
creasingly used in the work of the State Power Board. 
Roads and Waterways Administration 
For the last few years stereo-photogrammetric methods have been 
increasingly used to select suitable routes of roads. The ground is 
examined in stereo models and alternative routes of the roads are 
estimated from technical and economical points of view. When neces 
sary the photogrammetric examination is completed by field reconnais 
sance, and the route of the road is staked out more in detail on the 
ground. Sometimes it has also been able to reduce the outdoor works to 
putting out the photogrammetrically found route of the road defi 
nitely. In these cases earthwork quantities have been determined and 
the roads been designed in detail by photogrammetric methods. 
For the photogrammetric adaptation most of the County Idighway 
Offices are equipped by mirror stereoscopes and stereometers. The 
pictures used are as a rule contact prints — acquired from the Geogra 
phical Survey Office — on a scale of about 1:20 000 and longitudinal 
and lateral overlaps of 60 % respectively 40 %. 
To some extent projecting of roads has been done by using photo 
grammetrically produced large scale maps with small interval contours. 
~ W / * y V 
The Photo Section of the General Staff 
Its Photogrammetric Tasks and Organization. Photogrammetry is 
practised not only to train the staff of the Section for any photographic 
work required by the defence organization, but also to study and deve 
lop photogrammetric methods and equipment suitable for defensive 
purposes. No photogrammetric mapping or other photogrammetric pro 
duction is done except for training purposes. 
The photogrammetric work of the Section is done under the guid 
ance of a photogrammetrist by the personal in training at the time. 
Photogrammetric Methods and Instruments. The actual methods are 
in the first place rapid mapping methods, but stereo-methods requiring 
precision instruments and methods of non-topographic photogrammetry 
are also taught. The training tasks have included production of mosaics,