82 REPORT OF COMMISSION VII
J. NEDERLANDSE HEIDEMAATSCHAPPIJ AT ARNHEM (RECLAIMING OF POOR SOIL)
This Service, which strives for the cultivation and improvement of waste
and infertile grounds, uses aerial photographs primarily for mapping and only
secondarily for interpretation (e.g. for forest stand-inventory). For this purpose,
vertical photographs on a scale of 1:10,000 or larger are used. In order to obtain
the most exact data regarding the inventory, photos taken in the summertime
are most suitable.
K. WATERLOOPKUNDIG LABORATORIUM AT DELFT (RESEARCH OF HYDRAULIC
WORKS)
This Laboratory studies the influence of water on hydraulic works which are
to be built eventually, on banks and beds of rivers, with the aid of models.
Aerial photographs are used in such studies to observe the behavior of waves
with whirling, breaking and reverberation and to construct models which are
essentially true to nature. This interpertation must be completed with the aid
of ground surveys of wave height, current speed and depth of water. The scale
of the vertical photos will depend on the desired particular type of interpreta-
tion to be done. For studying the wave behavior, their lengths must be properly.
visible on the photos. Wave lengths may vary from some meters to upwards of
a hundred meters.
L. MEETKUNDIGE DIENST VAN DE RIJKSWATERSTAAT AT DELFT (SURVEYING)
The aerial photograph is used principally by this Service as an instrument
for mapping, with interpretation being only incidental thereto. In temperate
zones this consists primarily of distinguishing kinds of vegetation from each
other. When mapping buildings, interpretation of the species of stones sometimes
is possible from aerial photographs. Perhaps this kind of interpretation may
better be described as identification.
When mapping tropical regions, the interpretation of such factors as drain-
age pattern, slope gradient, and the height and species of vegetation may be of
value in connection with the mapping of areas.
M. KONINKLIJKE LUCHTVAARTMAATSCHAPPI/ AT SCHIPHOL (AERIAL SURVEYING)
As the Phototechnical and Cartographical Institute of the K.L.M. provides
for taking aerial photographs and also carries out mapping for principals, use
of photo-interpretation is only made as stated in L.
INSTRUCTION IN PHOTO INTERPRETATION
As photo-interpretation in the Netherlands has been employed by different
services for only a few years, instruction in this branch of science is still in its
first stage. The most important teaching institution during 1951 is the Interna-
tional Training Centre for Aerial Survey at Delft, established in 1951 under
the management of Prof. Dr. Ir. W. Schermerhorn. Persons of different nation-
ality trained by this Institute are eventually given a complementary training
both in the photogrammetrical methods of mapping and in interpretation.
Special teachers have been included to provide instruction in interpretation.
During the past five years a course has been given in photo-interpretation
at the Governmental University at Utrecht, with special emphasis on Geology
and Geomorphology.
Also from military quarters there is great interest in photo-interpretation.
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