the saving in time and money entailed in the utilization of photogram- 
metry at the stage of the design, but after the experience of the two 
past years at the National Road Board it is quite clear that the profits 
are considerable. 
Test work in the design stage 
In order to ascertain whether the theoretical accuracy ın numerical 
and graphic data in the design stage offered by photogrammetry is 
attained in practical work, the following test work has been carried out. 
In connection with the planning of national highway 1 Halsingborg— 
Stockholm the section Huskvarna—Gränna, a part-section about 15 km 
in length has been made the object of photogrammetric detail study. 
Longitudinal profile, coss-sections and maps with or without contours 
to the scale of 1:500—1:1000 have been drawn from photographs taken 
from an altitude of approx. 900 m. The treatment of the pictures has 
been carried out in a stereoautograph Wild A-8 provided with "profilo- 
scope”. The terrain is rather broken and much of it 1s wooded. The side 
slope in the cross-sections measures in certain cases 15—20 m. 
In this section a stretch of about 2 km has been selected to serve as a 
test strecht. 
The aim of the test was firstly to get an idea of the accuracy afford- 
ed by the conventional method of ground measurement and secondly to 
compare the accuracy of the photogrammetric result with that of the 
conventional result. 
The cross-sections and lengthprofile of the strech were measured on 
the ground by two measuring teames quite independently of each other. 
The first measuring team, referred to below as team I, carried out the 
measurement of the first km with great care and with a distance of 2 
m between the sections and a distance within the sections of 2 m. Team 
II performed the measurement in the conventional way, with a distance 
of 10 and 20 m between the sections. The point-positions within the sec- 
tions were determined by the form taken by the surface of the terrain. 
As measurement I is to be regarded as the most accurate conceivable 
recording of the surface of the ground, a comparison between measur- 
ing results I and II should give a good picture of the accuracy of the 
conventional method for the recording of the surface by cross-section- 
ing. 
A third measuring team also sectioned the stretch but as this team 
by mistake did not measure sufficiently long cross-sections, it was not 
possible to utilize this material to the full in the investigation of accu- 
racy. 
The photogrammetric measurement of the cross-sections and the 
length profile had to be carried out in connection with the treatment of 
the entire road-project, which had been performed in the way described 
in the chapter Design above.