ALTERNATIVE METHODS FOR MAPPING OF 
BOUNDARY POINTS 
An important task in connection with large scale 
mapping in this country, is to find the most suitable 
method for mapping of points which are not directly 
visible in the photographs, neither can easily be iden- 
tified in these under field examinations. 
Three methods had to be taken into consideration 
for the procedure to be used for the new 1 : 5000 map 
series. These are: 
a) The points are made visible by signalizing. To 
attain the sufficient accuracy is not the problem 
using this method. But to perform an efficient 
signalizing is very time — consuming. Some 
comments to this method will be mentioned in 
the paper. 
b) The points are not signalized. 
This method will be the main subject of the 
paper. and the aim of the investigations is to 
work out the best procedure and the accuracy 
of the different steps and the final result. Also, 
as far as an investigation work may give in- 
formations about the time consumption, this 
plays an important part. 
Shortly described the procedure of the method 
IS: 
The field operator equiped with a stereopair of 
paper contact — prints, a pocket stereoscope 
and a needle, try to identify a detail which is 
centred in the boundary point itself and make 
a prick in one of the photographs. If the point 
itself can not be identified, a visible point near 
the boundary is pricked, and the distance and 
magnetic bearing to the right one measured 
with a tape and a compass. In most cases the 
distance was shorter than 20 m. This material 
is used by the operator of the stereo restitution 
instrument, either by alternating looking at the 
paper prints and the instrument model, or mak- 
ing an intermediate step by transfering the 
pricks to the diapositive. 
This method will undoubtedly be superior in 
economy, but the question is whether it is suf- 
ficient in accuracy. 
c) Terrestrial measurements by compass traverses. 
Some tests are done, and the method is found 
accurate enough when having the magnetic 
anomalies under control. The traverses are con- 
nected to signalized points which are photo- 
grammetrically determined. The capasity of the 
method is relatively good, the very sheep equip- 
ment taken into account. It has, however, not 
been given sufficient interest to be further in- 
vestigated. 
SIGNALIZING — OR NOT? 
The necessity of these investigations is based on 
previous experiences in signalizing boundary points, 
and tests about the accuracy in measuring signalized 
points, carried out in other countries. 
These tests show that when having visible signals 
in the photographs, the accuracy is far good enough 
for the map series. But the experiences mentioned 
above have shown that signalizing boundary points 
in this country is difficult and expensive. À relatively 
large percent, some examples give up to 70 %, of the 
signals has not become visible in the photographs. 
And as the execution of the work has to be laid upon 
the estate owners, the quality will vary a good deal. 
The quality also depends very much on the forest 
covering the area. À complete signalizing is relatively 
easy to perform in the mountain and coast districts.