rea. 
  
Figure 3 Thermal band image of Urmqgi. 
Based on the values of digital count number for the thermal 
image shown in Figure 3 corresponding to each class, We 
have seen that the temperature of urban area was higher 
than that of vegetation area. 
Figure 4 Mask image of urban area. 
  
Fell 
  
  
Et 4642 L^: 
TEUE(RSE: 7688 Ep: 
cR: 0 LEE: 
Zt) 589429 Amy 1 
  
  
  
Figure 5 Histogram of urban area. 
  
    
    
        
      
  
    
  
  
    
  
   
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
SD. Mean 
value 
Urban 31.2 167.8 
Water body 34.9 36.8 
Bare ground 1 35.0 170.3 
Bare ground 2 33.2 182.0 
Soil 33.0 169.1 
Forest 42.5 126.9 
Vegetation 1 36.7 72.2 
Vegetation 2 34.8 119.1 
Vegetation 3 30.9 179.3 
  
  
Table 1 Mean value and S.D. of thermal band data. 
We can understand from the mean value on Tablel that the 
urban area temperature is higher than Vegetation area 
temperature. The high temperature of the urban area is 
mainly caused by the characteristic of urban surface. As 
cities and roads, buildings, and industrial areas, temperature 
in the city is relatively higher compared with their rural 
surroundings creating a heat island. In similar way, the 
temperature in other areas is also very high because of the 
strong bare soiled radiance. We can easily find out that the 
standard deviation values for forest area are very high 
because the forests have sunny sides as well as shadow 
sides. These sides temperatures fluctuate is considerably 
difference so the standard deviation values for forests area 
are very high. 
The standard deviation value of water body is higher than