must be available to the personnel in an attractive form and must be 
convenient to use, even for stereo-vision in the field with a pocket stereo- 
scope. For this purpose the prints -— cut to convenient size for stereo-vision 
of the whole area pictured — are pasted on light strong sheets of alu- 
minium (21X30 cm). See fig. 4. Company boundaries, forest ranger 
districts and new roads are marked on the photos. In the office and during 
transport the aluminium sheets are kept in boxes and in the field they 
are carried in cases provided with shoulder straps. General topographic 
maps serve as index to the photos. 
4. Training. Before receiving the photos the personnel is put through a 
2—4 days course of training, including practice in the field. Plans are being 
made to follow these courses by supplementary courses after a year. 
5. Photo maps. Contact prints serve most needs, but require supple- 
menting by special maps better suited to the recording of projects executed 
and the taking out of surveying data. For these purposes the company 
mainly makes use of photo maps produced by the Geographical Survey 
Office, scale 1: 10 000. Names, boundaries, some roads and the like (not 
stand boundaries) are marked on the photo map by letters and signs re- 
presenting particulars taken from the economie map or existing forest 
maps or information obtained in the field. If no photo map is available 
for a wanted region, the company first has an inexpensive photo map made 
on 1: 20 000 scale based on known bearing points and radial triangulation. 
From this a negative on 1:10 000 scale is made, and copies of this are 
made for practical use. Some of the photo maps are reduced to 1: 40 000 
or 1: 50 000 for general viewing purposes. 
6. Single photo maps. In forest districts where there is poor ground 
control, the company has employed a method formerly tried in Sweden, 
consisting of the enlargement of single photos to an approximate scale of 
1: 10 000, using general topographie maps as guide. Each print is made 
with a margin (overlap border) and provided with names, scale, arrow 
indicating north and the like, as on drawn maps. In addition particulars 
are given of length of shadows, correction of displacement due to central 
projection and so on. These single photo maps can to some extent be 
   
ve, 
Wg 
Bc 
Fig. 4. Prints pasted on sheets of aluminium (Korsnis design) and stereoscope 
with leg supports, Simonsson patent. 
13