International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B7, 2012 
XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia 
polarization power response is greater than the 
cross polarization power response. Also the co- 
polarization response shows higher horizontal 
response as compared to the vertical response, 
with two maxima at horizontal polarization. 
In case of road-2, which passes through the 
agricultural fields, in the outskirts of 
Ahmedabad, the total polarimetric response is 
less as compared to road-1. There is a single 
maxima around orientation angle 90° and 
ellipticity angle +45°. This difference in the 
polarimetric response of the two roads might be 
due to the orientation factor, as road-1 is 
oriented perpendicular with respect to the radar 
look angle, and since it also passes through the 
built up area, hence, due to cardinal effect, a 
strong backscatter signal might be observed, 
thus giving high backscatter, while in case of 
road-2, it gives a low polarimetric power 
response, as it is parallel to the radar look angle. 
The polarimetric response of road-2 is greatly 
similar to that of the bridge, indicating similar 
orientation with respect to look angle. 
  
  
  
  
  
  
  
  
Co-polarized Signature Cross-polarized Signature 
Figure 3.2(a): Polarimetric response of Road-1 
  
  
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Co-polarized Signature Cross-polarized Signature 
Figure 3.2(b): Polarimetric response of Road-2 
  
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Co-polarized Signature 
Cross-polarized 
Signature 
Figure 3.2(c): Polarimetric response of Bridge 
3.3 Vegetated Land: 
Figure 3.3(a) shows the polarimetric response 
(co-pol and cross pol) for vegetated land in the 
outskirts of Ahmedabad City. From the study of 
its polarimetric signatures, it is seen that the co- 
polarization backscatter values are greater than 
the cross polarization power values, and also 
there is an overall high backscatter. This might 
be due to the fact that EM waves undergo high 
multiple scattering on coming in contact with 
the dense vegetation cover, with majority of 
volume scattering. The . co-polarization 
signature shows greater response near -50° 
ellipticity angle, being almost constant at 
various orientation angles, while the cross 
polarization signature shows two maxima at 
horizontal polarization. However both the 
responses show weak vertical response. 
  
  
  
  
  
    
  
  
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Co-polarized Signature Cross-polarized Signature 
Figure 3.3(a): Polarimetric response of Vegetated 
Land 
3.4 Open Field and Water body: 
In open field, due to less multiple scattering and 
greater surface scattering, it causes less 
backscatter. The cross polarization power 
response is higher as compared to co- 
polarization power response, showing the 
depolarization of the signal. 
Figure 3.4(a) shows the polarimetric response 
(copol and cross pol) of a waterbody (Kankaria 
Lake) in Ahmedabad city. On analyzing the 
signatures it is seen that the co-polarization 
response is less than the cross polarization 
response. The copol signature shows a higher 
response at an orientation angle around 180° 
and ellipticity angle near -45°. Also there is not 
much variation in the backscattered power 
response ranging over various ellipticity and 
orientation angles, indicating less backscatter 
from the lake. The cross polarization response