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 
4.2 Experimental results 
By the procedures of persistent scatter InSAR, refined 1520 
persistent scatters are detected from 26 radar images by the 
statistical computation of time series of amplitudes. Figure 5 
displays the distribution of all the 1520 persistent scatters 
marked with yellow points and superimposed onto an optical 
Lantude tex? 
    
    
Longitude (Dez : 
Figure 5. PSs superimposed onto an optical orthoimage 
3128 
ws 
is 
A 
Latitude (D3eg.3 
  
  
MEAN 
400 600 
0172 200: 
Figure 6. Two-dimensional Delaunay 
network based on the image 
orthoimage download from GoogleEarth. The two-dimensional 
Delaunay network and three-dimensional Delaunay network of 
1520 persistent scatters are constructed based on image 
planar coordinates and Cartesian coordinates respectively. 
Figure 6 demonstrates the two-dimensional network reformed 
by lkm threshold. 4092 arcs, i.e., 4092 NDP observations are 
obtained from the planar network. Figure 7 shows the planar 
projection of three-dimensional network optimized with lkm 
threshold. 4502 arcs are generated in this network. The number 
of NDP observations of TDPDN is significantly more than that 
of planar network. Based on persistent scatter InSAR 
algorithm, the subsidence of persistent scatters is derived 
according to two-dimensional network and three-dimensional 
network respectively. The statistics of subsidence is displayed 
in table 2. The maximum subsidence velocity detected with 
two-dimensional network is 21.0 mm/a and the minimum is 6.0 
mma, and the average subsidence velocity is 16.8 mm/a. The 
maximum and minimum subsidence velocities achieved by 
TDPDN are 18.3 mm/a and 7.8 mm/a respectively, and the 
average subsidence velocity is 13.7 mm/a. 
121.52 
EM 
121.56 
Longiaude tDez.i 
Figure 7. Projection of three-dimensional network on 
two-dimensional plane in study area 
Table 1. The parameters of 26 ERS-1/2 SAR images used in this study. 
  
  
Temporal Normal Temporal Normal Temporal Normal 
No. Imaging date baseline baseline | No. Imaging date baseline baseline | No. Imaging date baseline baseline 
(day) (m) (day) (m) (day) (m) 
1 1992.06.06 -1459  -1249.61| 10 1996.03.26 -70 255.64 1:19. 1999.12.21 1285 -691.39 
2... 1992.09.19 -1354 -1139.68| 11 1996.06.03 -1 -84.260 | 20 | 2000.05.09 1449 . -1445.09 
3 1993.04.17 -1144  -1189.5 | 12 1996.06.04 0 0 21 2000.06.13 1475 -619.88 
4 1993.07.31 -1039 -1088.19| 13 1997.11.11 534 -328.45 | 22 2000.09.26 1554  -1206.38 
S 19934113 -934 -568.70 | 14 1998.02.24 611 18.0 23 2001/1120 1986 -959.86 
6 1995.04.10 -421 -639.80 | 15 1998.03.31 635 -572.38 | 24 2002.06.18 2200  -1839.42 
7. 1995.10.02 -246  -1131.73| 16 1998.05.05 722 -1086.85| 25 2002.07.23 2226  -1041.75 
8 — 19960219 -106 — -1445.48| 17 1999.04.20 1041  -1207.12| 26 2002.08.27 2253 66.43 
9 1996.03.25 -71 155.96 | 18. . 1999.11.16 1259 -736.70 
  
  
  
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