Previous Map Plates 
  
Scanning 
  
  
  
  
Raster Data of Old Version 
  
    
  
  
  
  
Resampling for Registration 
  
  
  
  
  
  
  
  
From Second Revision 
— — Raster Data of Old Version 
  
  
  
  
  
Aerial Photograph 
| 
Refer 
r--- — Numerical Plotting 
| | 
b ceo Vector Data of Changed Parts 
Refer 
  
Raster Editing 
  
  
  
  
  
  
Raster Data of Revised Version 
  
  
— Output from Themal Printer 
  
  
  
| 
  
  
Output from Raser Plotter 
  
  
  
| Output for Cheking 
  
legend 
  
Revised Map Plates 
AAS 
  
  
process 
  
  
digital data 
  
AAS AAAAAAAAAAAAAAAAAA 
  
  
analog data 
CAF AANAAAAAS AA 
Figure 1 Flow of the Raster Básed Revision Method 
of the previous map is combined with the 
registration plate on the white film, and this 
combined plate is used for scanning. After 
scanning, the coordinates of registration marks of 
each plate and corner marks(marks which show the 
positions defined as the intersections of sheet 
lines) of the black plate are measured. After the 
measurement, transformation coefficients between 
the black plate and UTM coordinate system are 
calculated from the coordinates of corner marks, 
and those of between the black plate and other 
plates from the coordinates of registration marks 
of the black plate and those of other plates. 
Finally, after resampling black plate so that the 
upper sheet line coincides with the line direction 
of raster data, each plate except black is 
resampled to be adjusted to black plate using 
transformation coefficients calculated above. The 
time which takes for resampling were surprisingly 
improved by the method which directly resamples the 
compressed data by run length encoding. 
518 
2.3 Numerical Plotting 
In this stage, vector data of changed parts are 
obtained by an analog plotter with coordinate 
encoders. Exterior orientation, data aquisition of 
changed parts, and the adjustment with raster data 
of the previous version map are performed on  EWS. 
The development of this stage is ongoing. 
2.4 Raster Editing 
In this stage, raster data corresponding to each 
plate of the previous version map is edited on the 
screen while displaying vector data of changed 
parts as background. The basic edit operations 
are drawing and erasing, which are attained by the 
movement of mouse. It means an operator gets a 
scriber and a eraser on the screen of EWS. 
2.4.1 Functions of Raster Editing Program Table