56 
Another example for highest plotting rates is : the Graphic Out 
put System 1675 of Messrs. CALCOMP/USA by means of which on a 
display screen of 8 cm x 8 cm (16,384 addressable positions 
each in x and y) a plot is generated and subsequently exposed 
on 16 mm or 35 mm film by means of a shutterless camera. 
Depending on the intensity of the beam for one position, up to 
32 gray levels can be achieved (in practice about 16 gray levels 
will be chosen). At a mean beam intensity, a maximum of 400,000 
increments per second are realized. Since with this type of 
system a photographic enlargement of the 16 mm or 35 mm film is 
usually desired, the line quality is in most cases not consid 
ered adequate for cartographic requirements. 
These briefly outlined courses of instrument development in 
photogrammetry and cartography call, however, for a comment: 
a) From a constructional point of view, the photogrammetrie 
instrument manufacurers have so far been independent to a 
wide extent, this means that specific firms (such as ZEISS, 
WILD, and others) constructed instruments according to given 
photogrammetric measuring theories, these instruments being 
nearly exclusively used again for photogrammetric tasks only. 
b) An independent cartographic instrument manufacture (for 
large-capacity equipment !) in this specific sense does not 
yet exist. Here the situation is that cartography selects 
suitable instrument from a range of instruments used by dis 
ciplines more or less related to cartography. Lately, how 
ever, cartography makes demands in increasing number (in 
particular accuracy requirements) on the instrument manu 
facturers but considering that these requirements call for 
high investments and corresponding constructional experience, 
only a few firms are willing to satisfy them. 
c) The photogrammetric as well as the cartographic systems com 
prise to an increasing degree single instruments or parts of 
instruments of different manufacturers (for instance when 
the primary system is supplemented with a computer and a dis 
play) . This tendency (which is likely to increase)requires 
that photogrammetry and cartography point out and explain