Trondheim in 1973. Furthermore, several leading photogrammetrists from 
- abroad have visited Finland and Finns, in turn, have participated in 
symposia, congresses, meetings, courses, and thematic days abroad both 
as members and as lecturers. 
Aerial Photography 
  
During the said four-year period the National Board of Survey has photo- 
graphed with its own DC-3 aircrafts. When necessary, it has also photo- 
graphed at low altitudes with a hired Piper Navajo aircraft. The private 
engineering firm Finnmap procured a new Partenavia Victor aircraft in 
1973 and a Lockheed Lodestar aircraft later in the 1970s. In 1975 the 
National Board of Survey bought a Rockwell Turbo Commander 690A propjet. 
A jetplane Iljushin 28 of the Air Forces is available for high-altitude 
flights (about 9 000 m). 
The following new aerial cameras have been procured in the years 1972 - 
1976: RMK A 2 15/23 (Zeiss West Germany) (1 camera), Wild RC 10 UAg. II 
(2 cameras, focal length 15 cm) and a lens NAg.of 21 cm for the other 
RC 10 camera. In addition, three Zeiss RMK A 15/23 cameras and one Wild 
RC 8 UAg camera, as well as one Wild RC 7 aerial plate camera have been 
available at the end of the term. 
Towards the end of the term the National Board of Survey procured both 
automatical developing equipment and a printer. At the same time plastic- 
based materials have been increasingly used in printing. 
. The annual output has been about 15 000 black-and-white and about 1 000 
color or false-color photographs. About 31 000 prints, 21 600 enlargements 
and 7 700 diapositives have been made from these yearly. 
Most photographies have directly served the production of maps, but the 
color and false-color photographies, in particular, have been specially 
made for various interpretation applications.