OR 1:25,000 
ponsible for 
graphic maps 
overing whole 
ision work of 
vision method 
pposed to be 
1ethod (Koide 
l for getting 
ing method is 
rdinary stereo 
the following, 
on system for 
nap and the 
IS system are 
1:25,000 scale 
raster type 
ierated after 8 
phic map are 
'ecise scanner 
'cond revision, 
d parts 
| vector form 
1 in the stereo 
ple updating 
r single aerial 
ale maps are 
d overlaid on 
re recognized 
developed by 
are edited 
Revised raster map 1s output onto film by laser 
plotter. 
4.2 Merit of the simple updating system for 
1:25,000 scale topographic map 
This system 1s devised to be used practically 
for map revision. First of all, considering 
aerial photograph used in the present revision 
work 1s not film but print and A3 size scanner, 
which can scan full size of aerial photograph, 
is expensive, A4 size scanner is adopted. 
Second, scanning pitch is more than 60 pm 
(up to 100 pm) and scanned photograph is 
represented with 32 colors (or grey scale) , 
which makes data volume not so large. Third, 
reduced image from 1/2 to 1/32 are kept in 
order to make the operation smooth. 
Besides these devices, as generalization is 
often conducted in the editing work of 
1:25,000 scale topographic map, precise 
shape of each building is not required, which 
makes the demerit of simple updating method 
very small. As the demerit of this system, 
orientation in mountainous area is difficult 
because control points are not acquired easily. 
Figure 3 shows the example of aerial 
photograph overlaid on raster map. 
  
1/25, O0 ONSEISIF(VRC) 
  
  
  
TH 
Di 
  
ap 
  
  
L ee ele LEE diia al limi ai OLLI LT, [LE 
ru = OLLI. LI LLL Su 1. d D 1 
\ 
a \A 
  
  
  
Figure 3 : Example of aerial photograph overlaid on raster map 
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