procedure). The absolute orientation is done by the computer using direct ground control 
or control from the aerial triangulation. All detail points in the model are now transformed 
into the map system and these coordinates are fed into an automatic drawing machine. It 
will be clear that during the measurements in the photogrammetric instrument the 
coordinates have to be provided with the necessary codes indicating e.g. which points have 
to be connected by lines etc. Additional information can be added for place, size and 
direction of symbols and names. It is reported that the application of this procedure gives 
a time saving between 20 and 30%. To obtain this saving a stringent organization of 
preparation, reconnaissance, completion measurements and map editing is required. 
IV.1.2. The Topographic Service reports about a special project consisting of a Digital 
Terrain Model of certain aereas. The registered coordinates have been used to provide 
(via a computer) intervisibility data and perspective terrain drawings. 
IV.2. Research 
The Cadastral Service and the University of Delft participated in a test, organized by 
Comm. C of the OEEPE on town mapping from aerial photographs. The Topographic 
Service and the ITC participated in the work of the Commissions D and E of the OEEPE. 
At the ITC special attention is paid to a systematic approach of the planning of photo- 
grammetric surveys (70, 71, 74, 76, 81). Experiments are going on in the field of ortho- 
photography and digital terrain models for engineering purposes. Results will be published 
in due time. 
The use of remote sensing data in a metric sense has been the subject of a special study 
by mr. Leberl. Results will be reported in a presented paper to the Congress (106, 107, 108, 
109). 
CHAPTER V. NON TOPOGRAPHIC APPLICATIONS OF 
PHOTOGRAMMETRY 
The Survey Department of Rijkswaterstaat has used Hasselblad cameras for special 
applications such as: 
a. determination of movements of ships on rivers and during launching 
measurement of height and direction of waves 
c. measurement of streams and water pollution using colour photography or various 
film filter combinations 
d. measurements of interesting ship-wrecks found in the newly reclaimed polders. 
CHAPTER VI. EDUCATION 
New developments of this field are: 
The move of the ITC (International Institute for Aerial Survey and Earth Sciences) 
from Delft to Enschede. This move was necessary since the available building at Delft was 
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