terial resulting from the preliminary planning. The main points of the 
road-line, i. e. its tangent-points and points of tangential intersection 
are established in the conventional way. Longitudinal measurement is 
carried out and the angles are measured with the theodolite, after which 
the road-line can be calculated as a polygon system. If the road-line has 
been staked out from a detail polygon system it is linked up with the 
same. If this is not the case the line can as a rule be connected up with- 
out difficulty with the polygon system with 1—3 km side used in the 
preliminary planning. A system of fixed points of altitude 1s laid out 
along the road-line in the conventional way. These points are of course 
necessary for, inter alia, the staking out of the roadbody in connection 
with the actual constructional work. 
The main points of the road-line are signalized with white-painted 
masonite discs measuring 40 X 40 cm before the photographing. Also 
certain points along the road-line at intervals of about 300 m are signal- 
ized. The signalized points are levelled and the height of the discs above 
the ground is stated. 
The reason why the road-line is signalized before the photographing 
is that in this way the connection between the photogrammetric mea- 
surements in the horizontal and vertical planes on the one hand and the 
staking out in the terrain on the other is established. 
The aerial photography is done with modern wide-angle cameras 
from a cruising altitude of about 800 m. The treatment of the pictures 
takes place in a stereograph Wild A 8. 
As a result of the treatment one gets the ground profile of the road 
and its cross-sections, as well as a detail map on the scale of 1:500— 
1:1000 with contours at 0.5—1 m equidistance over the areas where this 
1S necessary. 
The road-line is mapped in the light of the data from the staking out 
on the scale of 1:1000 and is then made to serve as a basis in the hori- 
zontal plane for the scale determination of the photogrammetric model 
and as control in the vertical plane in the direction of flight. The re- 
quisite other vertical control points are levelled after the photographing. 
The problems as to treatment now consist in steering the measuring 
mark of the stereo-instrument along the road-line and at right angles to 
the same. To solve this problem the firm of Wild has constructed the 
socalled profiloscope; se fig. 8. 
This procedure may be considerably improved by connecting up with 
the stereoautograph a coordinate-recording apparatus for the automatic 
printing and punching of horizontal and vertical coordinates in the 
coordinate system of the instrument. Conversion to the coordinate sys- 
tem of the ground and the presentation of data in the form of conven- 
tional lengths and altitudes for the points in ground profile and cross- 
sections are then rapidly executed by the date machine Facit EDB. 
Thanks to this automatization of the collecting of data the human 
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