to nature that influence the accuracy of these calculations. 
For this reason, it is not only the height accuracy of 
the measuring points, but moreover their right number and 
significant arrangement which have to be taken into con- 
sideration when determining morphological shapes. 
Recognizing these relations, the photogrammetrist encounters 
a number of problems in being responsible for procurement 
and storage of the terrain data, for the construction of 
the terrain model and its best possible adaption to nature. 
In view of the present status of photogrammetric equipment, 
there are two statements justified. 
- Photogrammetric height accuracy obtained from 
economical photo scales is sufficient for all 
civil engineering projects. 
- Due to its resemblance to nature, for the 
measurement of civil engineering projects, the 
analogue procedures will be preferred to the 
analytical ones. 
The question what and in which way - according to type and 
contents of terrain - has to be measured, raises a number 
of problems, which cannot be judged but by practical 
application. The Intercommissional Working Group IV/V 
"Civil Engineering" will have to formulate these questions 
and prepare them for discussion, so that a solution can be 
found in photogrammetric practice. 
Some thoughts are noted in the following. 
Let's examine three different types of terrain, the 
differences of which are characterized by their morpho— 
logical shapes. 
In case the terrain is plain or includes vast, continuously 
sloping surfaces the measurement of regular or irregular 
grid is to be recommended. In addition, a systematic scanning 
of such areas by automatically controlled xy-motion should 
also be taken into consideration.