VIDEOMAP is a system for superimposing digitized line graphics onto 
the associated photograph. This is implemented by displaying a vector 
memory segment on a HP high-resolution vector refresh screen and 
mirroring the display into the left eyepiece of the stereoplotter. 
The graphic data transferred by the computer to the VIDEOMAP controller 
is stored in the graphics memory. This graphics memory has an address 
range of about 524 mm x 524 mm, a resolution of 0.032 mm (both 
referring to the photo plane) and a capacity of at least 70.000 vectors 
/4/. The vector line width on the screen is about the same as the 
floating mark diameter. 
Fig. 2 shows the function blocks of the VIDEOMAP control unit. 
DIGITAL MAP 
  
  
  
INPUT BUFFER 
  
  
  
  
  
GRAPHICS MEMORY 
  
  
  
UPDATE DISPLAY AREA 
  
  
  
  
  
FLOATING MARK 
DISPLAY MEMORY POSITION 
  
  
  
  
  
  
  
UPDATE VIDEO IMAGE 
  
  
  
  
  
  
VIEWER 
VIDEO IMAGE 
  
  
  
Fig. 2: Structure of the VIDEOMAP Control Unit 
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