Oyama, Yoichi 
3)It is easy to judge whether the object protrudes over the surface because the position of viewpoint can be changed 
optionally (Figure 3). 
  
  
  
  
  
  
  
  
  
  
(a) (b) (c) 
Figure 3 : Tower (a), building (b) and mountain (c) for which protrusion is confirmed 
4) While the surface data are inputted as the test data of coordinate queue in the case of analytical plotter, the data are 
inputted in an interactive way, and as a result, the profile of surface can be instantly confirmed and input error is 
eliminated. 
The improvement was the result that the function of digital photogrammetry system was used as CAD. 
In the case of analytical plotted specialized in data input, the viewpoint is limited to upper position as a matter of course. 
Although there are many plotters which have a function to display vector data (superimpose) or are connected with 
simplified CAD, but there is a clear difference in the recognition of 3 dimensional space when compared with the 
photogrammetry system which operates on CAD. There is no difference in the acquisition of 2 dimensional data, but the 
effectiveness of digital photogrammetry system is clear in the application which necessitates the 3 dimensional 
verification like in the case of our study. 
6.2 Output of maps from CAD 
The effects of outputting maps from CAD are as follows. 
1)Many ground objects were converted into symbols because the priority was placed on the easiness for the users to 
recognize the topography. As preliminary processing for expressing the topography, many works of processing was 
necessary for data cleaning and structurization. 
2)Temporary output became easy during the course of works. 
CAD has played a role as a supplemental tool for the design works but its ability is insufficient for producing good 
looking prints as the final outcome of the studies. However, the efficiency of work is expected to be improved by 
making input and edition paying due attention to the expression of final maps from the initial stages based on the 
experimental results of our present study. Also, the improvement of efficiency at the time of renewal of map due to 
temporal change as well as frequent renewal of maps are expected by once converting these pieces of information into 
data. 
7 FUTURE STUDIES 
The certainty of works to extract ground objects has been enhanced by converting from the process based on analytical 
plotter to the process based on digital photogrammery system. However, this work is fully dependent on the interactive 
manual input of data by the operator for the individual objects. In order to enhance the efficiency, we are planning in the 
future to verify the method to acquire the topographic data in advance, and extract protruding buildings and 
topographies in blanket. | ; Ant 
This study is supposed to have a high affinity with the decision making support using the simulation function which is 
one of the important roles of GIS. In concrete, the method discussed in this study is considered to be effective for the 
analysis and numerical conversion of open space (spatial and visual openness) and sunshine rate of wide ranged urban 
areas. 
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International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000. 1101