Fig. 5 Q—Q  Leneth- angle - traverse tied to 
photogrammetrically determined 
pointse 
Some small investigations were made to tie in a staked out regularly 
system of straight lines by photogrammetric methods directly to the 
triangulation network, without use of any traverse network. Only pre- 
liminary results have been obtained. They are positive. 
4.2. Planimetry and contours. At the old method the planimetry was 
obtained by a field party consisting of one surveyor and usually three 
helpers, measuring with tape and compass from the staked out parallel 
lines. The capacity of work for the party ought to be about 3—10 hec- 
tares per hour or 0.1—0.3 hours per hectare. For the land appraisal the 
capacity ought to be about 10—35 hectares per hour or 0.05—0.10 hours 
per hectare. 
At the new method the photointerpretation indoors is executed by a 
landsurveyor and, to some extent, by a surveying-technician. The capa- 
city of work for one interpretor seems to be about 80—350 hectares 
per hour or 0.003— 0.013 hours per hectare. The photointerpretation 
included interpretation of planimetry, some stand elements and land 
appraisal. Preliminary field inventory and measuring of the sample 
plot as basis for the photointerpretation requierad about 0.001—0.009 
hours per hectare. In one case control from helicopter of 35 000 hectares 
low-producing land far in north-Sweden was executed in 9 hours, of 
which 7 hours were effectiv time for work. It ought to be possible to 
execute the control from helicopter with a capacity of about 500—5 000 
hectares per hour or 0.0002—0.0020 hours per hectare. It is obvious 
that the new method is more rapid than the old one and also seems to 
be more economical. 
The basic advantage of the new method is that the field work is di- 
minished and in the main concentrated on the high-producing areas. 
That was possible to perform by photointerpretation and the use of 
helicopter.