International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B7. Istanbul 2004 
  
Paved 
     
  
LVR > 15% 
  
  
— Jd: 
  
  
LVR 21596 
     
   
        
   
     
   
  
   
  
Satisfaction 
in the whole local area 
CVA>AIVA 
«. M 
Relatively wide dimension 
in the local area 
Shortage 
   
  
       
  
       
elatively narrow dimensio 
in the local area 
    
   
  
in the whole local are 
  
  
Relatively wide dimension 
   
    
   
    
   
Satisfaction 
in the whole local area 
CVA?AIVA 
n" 
Shortage 
in the current land use 
   
elatively narrow dimension 
in the local area 
  
      
in the local area 
  
True,” 
  
[ :Parcel level 
False CI :Local area level 
CC) :Status 
  
  
Figure 3. Decision tree methods developed in this study. This method includes 4 stages and 9 branch points. 
vegetation-covered area depends on its individual dimension 
since a vegetation-covered area, which is attended with large 
dimension, has a possibility to become a core of greenery in 
a local area. Thus we calculated individual dimensions of 
VA, called IVA. IVA is the number of pixels of a VA, which 
form a region in isolation from each other. As the standard of 
local comparison, the average of IVAs, AIVA, in a local area 
is calculated as follows. 
N 
IVAi 
AIVA = Nx (2) 
i=1 
where N is the number of the formed regions of a 
vegetation-covered area in the local area. 
2.3.5 Decision Tree Method: Figure 3 shows the decision 
tree method we developed in this study. This method includes 
4 stages and 9 branch points. On the first and second stages, 
investigation from both sides of land use and land cover is 
carried out by pixel as parcel level processes. We divided 
land use categories into two classes: a paved area and an 
unpaved area. While the paved area contains industrial area, 
residential area, commercial area, road, and public space, the 
unpaved area includes forest/grassland, agricultural land, and 
park/green zone. 
As the local area level process, the analysis of VA in a local 
area is situated on third and forth stages. Comparison 
fL 
o 
490 
between LVR and a standard value of 15 % is performed so 
that it is necessary for greenery planning to clarify the 
vegetation cover ratio in a local area. Then, through the 
calculation of a difference between the dimension of CVA 
and the AIVA, the relative feature of a vegetation-covered 
area in a local area is indicated. 
The result of the decision method contains 6 kinds of status; 
"Satisfaction" means the satisfaction of standard vegetation 
cover ratio. This status includes a recommendation to 
conserve the CVA because it composes the local greenery in 
conjunction with other VA. "Satisfaction in the whole local 
area" shows that VA in the whole local area satisfy the 
requirement although there is not a CVA at the center of the 
local area. It implies an advisement to conserve the VA 
totally in the local area. Two of them mentioned above 
belong to the group serving the need for the greening of 
prefecture policy. On the other hand, "Shortage in the whole 
local area" reveals the lack of VA in the local area. This 
status suggests recommendation of greening since there is the 
lack of the dimension of VA in the local area. "Shortage in 
the current land use" shows there are no CVA and the shortage 
of VA in the local area even though the current land-use 
category is allocated unpaved area. It is concerned with the 
usage of the current land use. "Relatively wide dimension in 
the local area" and "Relatively narrow dimension in the local 
area" show the relative feature of the CVA in the local area 
where there is the shortage of greenery. The one reveals that 
the CVA has a potential for becoming the core of green belt 
because it has larger dimensions than AIVA. The other 
indicates that since the dimension of CVA is smaller than 
Int 
ta