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The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B4. Beijing 2008 
Figure 2. ASTER image and control points for correction 
Figure 3. SPOT5 image and control points for correction 
Figure 4. IKONOS image and control points for correction 
After selecting control points, correct original image by 
quadratic polynomial method for correction, and resample by 
Nearest-neighbor, then select 16 control points in ASTER image, 
16 control points in ETM, 16 control points in SPOT5, 18 
control points in IKONOS. Research on the corrected points 
precision in different types of remote sensing images, through 
compare the test points coordinate in topographic map with the 
corrected images. The result can be referenced to Table 1. 
Method of 
correction 
ASTER 
ETM 
SPOT5 
IKONOS 
Nearest- 
neighbor 
25.0m 
27.8 m 
20.9m 
6.7 m 
Table 1. the corrected points precision of four remote sensing 
images 
2.2 Research on precision of geometric correction of remote 
sensing images by data of portable GPS. 
Obvious ground features are selected as portable GPS control 
points, select obvious cross junction etc. 22 control points in 
sum, for geometric correction of ASTER, ETM, SPOT5, and 
IKONOS, the ways are ditto (except Nearest-neighbor), the 
correction images are omitted. Then select 22 control points in 
ASTER image, 21 control points in ETM, 18 control points in 
SPOT5, 18 control points in IKONOS, evaluate the point 
precision of the selected points which are considered as test 
points, the detailed result can be referenced to Table 2. 
Method of 
correction 
ASTER 
ETM 
SPOT5 
IKONOS 
Nearest- 
neighbor 
20.0m 
25.7 m 
23.8m 
10.1 m 
Table 2 .the precision result of correction by data of portable 
GPS 
Compared with the corrected points precision of calculated 
control points in topographic map, for ASTER and ETM image, 
the corrected precision is a little higher by data of portable GPS, 
it shows that the control points are collected by portable GPS 
can replace calculating on 1:50000 topographic map; however, 
for SPOT5 and IKONOS image, the corrected precision is lower 
by data of portable GPS. So it is not suit to use surveying 
control points by portable GPS as correcting SPOT, IKONOS 
images. 
2.3 Research on precision of geometric correction of remote 
sensing images by data of GPS for specialized. 
Collect 26 control points in field by GPSRTK (Trimble5700), 
and select 16 of all to make geometric correction for ASTER, 
ETM, SPOT5 and IKONOS images, the ways are ditto. Then 
select 21 control points in ASTER image, 17 control points in 
ETM, 15 control points in SPOT5, 16 control points in 
IKONOS. Evaluate the point precision of the selected points 
which are considered as test points, the detailed result can be 
referenced to Table 3. 
Method of 
correction 
ASTER 
ETM 
SPOT5 
IKONOS 
Nearest- 
neighbor 
17.9m 
22.4 m 
13.2m 
4.8 m 
Table 3. the points precision of correction by data of GPSRTK 
Compared with the corrected points precision of calculated 
control points in topographic map, the corrected precision are 
all improved by data of GPSRTK, but the improved level of