Ali Farrag, Farrag 
  
4. QUANTITATIVE ANALYSIS OF RESULTS 
In order to be able to obtain quantitative numerical results, the area on the ground corresponding to each pollution level 
was computed using the facilities available in the software. Also the maximum transport distance, from pollution source, 
of each of these levels was measured on the screen and given in the following tables. The data in these tables are 
corresponding to the sub image, which is corresponding to 12 km x 17 km on the ground. These data are represented 
graphically in Figure 3, where the cumulating of the extracted polluted area is represented (in square km) on the ordinate 
and pollution levels are represented on the abscissa. The identification of pollution levels (as low, medium and high) is 
suggested based on the location of the contamination with respect to the factory, where the closer places to the factory 
are expected to suffer from higher contamination. 
  
  
rn aa FN N 
— N de Az QU 
  
  
  
  
  
  
  
  
  
No Identification Results from 1995 image Results from 1998 image 
Area (m^) Dispersion | Area (m^) Dispersion 
(m) (m) 
1 Desert 139526400 = 202024400 - 
2 Low contamination * 47455200 11381 223600 5247 
3 Medium contamination * | 13277600 6579 1414000 4414 
4 High contamination * 3740800 4589 338000 1684 
Y* 64473600 1975600 
  
  
  
  
Table 1. Results of analyzing the data of the unsupervised classified image windows, plates 3 &4 
  
  
  
  
  
  
  
  
  
  
Class Identification Results from 1995 image Results from 1998 image 
No. Area (m^) Dispersion | Area (m^) Dispersion 
(m) (m) 
1 Desert 53329200 - 202802000 - 
2 Low contam. * 75561200 15431 734400 6420 
3 Medium contam.(I) * 38034400 12569 232000 3113 
4 Medium ontam.(II) * 19698400 6512 140000 2245 
s High contam. (I) * 10546400 5760 66000 2017 
6 High contam. (II) * 6830400 4521 25600 2000 
Ii* 150670800 1198000 
  
  
  
  
  
  
  
  
Table 2. Results of analyzing the data of the stretched green band, plates 5 &6 
  
  
  
  
  
^2 160 
£ 
A 
140 
D 
£1 
© 120 
b 
N 100 
d 80 
5 
© 60 
S 40 
u 
o 20 
O 
e 0 
High Medium 
Relative contamination intensities 
+ Image (95) Image (98) 
4 Green band (95) yGreen band (98) 
Figure 3. Graphical representation of the detected polluted areas 
5. CONCLUSION 
  
52 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000.