Mt. Hinokiboramaru N This black frame shows the range of 
: Tokyo the study area of this paper. 
e 0 500 1000 m 
n ———-Aá' 
This black frame shows the 
range of a map in Fig-5. 
     
   
  
  
  
  
  
     
  
       
  
  
    
  
  
         
  
  
   
  
  
   
  
    
  
      
  
  
   
  
  
      
    
  
  
    
    
   
  
   
    
          
    
     
  
    
  
   
EA EE SY AVA 
M 
   
   
  
   
       
   
  
   
ZZ 
N 
Mountain trai 
= 
   
  
  
  
  
EN Scriously-deteriorated areas 
7777. Moderately-deteriorated areas 
Fig-4 Results of the interpretation of the 
aerial photograph's 
    
  
  
     
E COE 
  
= à 22) $ pa 
S SHE vd 
Fig-2 Study area extent of deterioration and the scale of topographical poin: 
conditions. Fig-! 
2. GEOMETRIC CORRECTION OF AN AERIAL 3. INTERPRETATION OF AERIAL po] 
PHOTOGRAPH PHOTOGRAPHS easil 
At first, geometric distortion of an aerial photograph Secondly, degrees of forest deterioration are 
due to topographical unevenness is corrected(Fig-3) investigated using aerial photographs(Fig-4). The Fron 
using DEM. Therefore, a relatively simple method has forest was classified into three categories; seriously- tree: 
-been developed and its accuracy is examined. Basic deteriorated areas, moderately-deteriorated areas and whic 
idea of this method is the same as the geometric ^ areas without deterioration. In the seriously- 
correction using affine transformation. This method deteriorated areas, the ground surface can be seen even 
however , can correct distortion by compensating from the air due to the collapse of trees, and in 
positional errors due to the relative difference of | moderately-deteriorated areas, trees without canopies 
elevation. Average positional error is approximately are found. 
9m. It is concluded that this method has an satisfactory 
accuracy for this research considering the spatial 4. GROUND SURVEY 
  
In order to verify the interpretation results, a 
ground survey is carried out. In this ground 
survey, the degree of deterioration and 
the percentage of dead tree, a tree species, 
were examined at the twelve spots, and the 
longitude and latitude of ground survey spots 
are measured using Global Positioning 
System (GPS). To make a measurement error 
as small as possible, measuring was repeated 
HPs La at least four times in the same spot, and a 
Original data Corrected photograph mean was calculated. The point where the 
variation of observation values was larger 
  
    
    
  
  
  
Fig-3 An aerial photograph 
714 International Archives of Photogrammetry and Remote Sensing. Vol. XXXII, Part 7, Budapest, 1998