The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B4. Beijing 2008 
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affirmed that variant this is most credible in the sense of 
correctness results. Taking into account exclusively accuracy 
aspect of geometrical correction of the Resurs DK-1 source 
images it was affirmed that variant based on independent 
delimitation of polynomial coefficients is well-founded. It was 
affirmed that obtainment of the equal results of geometric 
correction in analyzed variants requires the use as much as 18 
control points in the variant basing on RPC delimitation. It 
should treat this variant as alternative in the case of the bounded 
access to the full metadata of the Resurs DK-1 image. On the 
basis of the thorough analysis of the individual variants of 
geometrical correction was affirmed, that the very high 
resolution Russian satellite data can be corrected on the level 
accuracy below half pixel of the source image. 
3.3 Requirements of the orthorectification process of the 
Resurs DK-1 images 
The influence of ground height difference on accuracy of 
orthoimage generated from nadir satellite images is smaller than 
in case of aerial photographs. Therefore to their 
orthorectification is possible to use of Digital Elevation Model 
with less accuracy. The source of this height model can be 
photogrammetric measurement on the aerial or satellite images 
with use correlation methods. The accuracy location of the 
situational details on the orthoimages is depends on accuracy of 
geometrical correction of the source Resurs DK-1 images. 
Knowing the orbital parameters and off-nadir viewing angle of 
satellite the theoretical analysis of orthoimage accuracy in the 
function of the accuracy of geometric correction of the source 
images and terrain characteristic was realized. Analyzing of the 
accuracy of the stage of orthotrctification process of 
Resurs DK-1 images was affirmed that for purpose of 
generating of orthoimage which attend of accuracy criterion of 
topographical map in the scale 1:10,000 it should: 
• perform the geometrical correction using sensor 
orbital data and measure of the minimum 5 ground 
control points as well as digital elevation model with 
accuracy better then 12 m; 
• perform the geometrical correction of the source 
images with delimitation of minimum 4 polynomial 
coefficients and measure of digital elevation model 
with accuracy better then 6 m. 
Taking into account of the recommendation for 
orthorectification process of the Resurs DK-1 scenes it is easily 
to notice that influence of terrain denivelation on the 
orthoimage accuracy is on so many small, that for his 
elimination in the majority of cases is sufficient measure of 
height terrain points with accuracy around 4 m. The source of 
such set points can be correlation methods of the measurement 
realized on digital aerial images in the scale 1:26,000 or 
panchromatic very high resolution satellite (VHRS) images for 
example Ikonos. However the economic aspect of automatic 
correlation measurement of DEM in the face of requirement of 
his accuracy caused that in the interest area was founded the 
Shuttle Radar Topographic Mission (SRTM) program. On the 
basis of the statistical analysis of SRTM model realized in the 
Institute of Geodesy and Cartography was affirmed that his 
accuracy on the area of the Poland is 2.9 m for flat and 5.4 m 
for hilly terrain. The values of statistical parameters showed 
that the interferometric measurement contain the systematic 
error component of height. After elimination this component 
the absolute accuracy of SRTM model was 1.0 m for flat and 
2.7 m for hilly terrains. In the face of above mentioned was 
showed that the SRTM DTED-1 height data represented each 
terrain form ensure the accuracy of orthoimages in 1:10,000 
scale generate from Resurs DK-1 images. 
3.4 Estimation of the orthorectification process of the 
Resurs DK-1 source images 
Estimation of accuracy of the orthorectification process was 
RMSE characterized accuracy position of situational details on 
orthophotomaps calculated on the basis of differences between 
coordinates reading on orthoimages and catalogue coordinates. 
Analysis of accuracy of orthoimages has been performed using 
the Image Station Ortho Pro software tools. The orthoimages 
taking into account the best results of geometrical correction in 
the individual variants were generated. Estimation of accuracy 
of orthoimages generated from Resurs DK-1 data has been 
realized on the basis of 18 independent check points defined for 
Cracow test area and 23 defined for Warsaw test area. In 
ortorectification process the corrected data set of the SRTM 
points with accuracy of 1,1m for Cracow test area and 0.8m for 
Warsaw test area was used. Results presented in (Tab. 3) refer 
to the orthoimages generated with lm pixel size. For all 
variants of geometrical correction the obtained orthoimage 
accuracy corresponds to the accuracy of the base maps in scale 
1:10,000. Additionally, for variant basing on the use of rigorous 
mathematical model of satellite sensor of Resurs DK-1 the 
accuracy was correspond with the accuracy of the base map in 
scale 1:5,000. It was affirmed, that the accuracy of orthoimages 
generated with pixel size 0.5 m is only imperceptibly higher. 
Characteristic of geometrical correction variant of Resurs DK-1 images 
RMSE XY in meters 
Warsaw test area 
Cracow test area 
THE QUALITY ASPECT 
Rigorous model with measured of 8 ground control points 
0.62 
0.61 
Polynomial coefficients calculated on the basis of 24 ground control points 
0.56 
0.61 
THE ECONOMICAL ASPECT 
Rigorous model with measured of 5 ground control points 
1.12 
1.23 ! 
Polynomial coefficients calculated on the basis of 12 ground control points 
1.66 
1.87 I 
Table 3. Results of orthorectification process in quality and economical aspects of geometric correction of the Resurs DK-1 images