Finland 
8 
RMK 10/18 X 18 and the RG 5 a -Aviogon. Contour lines have been traced with intervals 
of 1, 2 or 5 m. Also an aerotriangulation by the Ekelund-method, comprising 240 km 2 has 
been executed. In addition to this, a private company has mapped 113 km 2 with a Wild A 8 
in 1 : 4 000, one-meter contours, photographed with the Aviogon. 
Other applications of aerial photographs. 
Since 1948, rectified enlargements or »photo sheets» at 1 : 4 000 have been used as a basis 
for communal tax equalization maps. For this purpose the communities are 
photographed with a normal-angle camera to the scale 1 : 20 000. For determining the 
enlarging ratio a scale check line is measured in the field on about every second or third 
picture. The property boundaries are transferred on the enlargements from cadastral maps. 
In the field the soil is classified according to its value for farming or forestring purposes, and 
the results are compiled on the enlargements. The:e tax equalization maps 1 :4 000 are now 
covering an area of about 120 000 km 2 , which is about 60 % of the whole country, excluding 
the very sparsely settled northernmost part. 
The percentage of the photogrammetric work from the total cost of tax equalization mapping 
is about 20, which shows that the employment of aerial photography has definitely improved 
the production of map basis for so far-reaching a work as this. 
In recent years the use of aerial photographs in preliminary investigations for highway 
planning and in mapping of the highway areas has started in Finland. The route to be 
investigated is initially planned using stereophotographs 1 : 20 000, which give the relief of 
the terrain and also the approximate quality of soil according to the vegetation. After the 
approximate highway line is stereoscopically selected, partial enlargements 1 : 2000 of the 
pictures are made covering the line with an about 1 km wide strip. From these enlargements, 
made on transparent paper, inexpensive light copies are taken for working maps. 
During the field investigation property boundaries, relief features, buildings, different 
types of land and other necessary features along the planned line — which can be altered 
in the field — are compiled on the photo enlargements, thus getting a map which is suitable 
for the final technical planning of the highway. 
Rectified enlargements of aerial photographs at scales 1 : 1 000— 1 : 4 000 are also used 
as map basis for planning ditching and land clearing as well as drain- 
i n g and water supply investigations. These plans cover about 350 km 2 annually. 
The plan is plotted on the enlargements mads on transparent paper, thus being possible to 
get light copies which contain both the map base and the plan. 
Rectified enlargements are also used for planning of new cable lines and 
mapping the old ones. 
Suomalaisen Kirjallisuuden Kirjapaino Oy Helsinki 1956