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EM gives good 
the low altitude 
1 4.55m. As the 
ng. The results 
expected while 
îe SD value is 
1. As the DEM 
ï high values of 
, i.e. bare earth 
of natural watersheds. The DEM accuracy, analysed both at the 
point mode and the surface mode, produced good results. 
The geometric accuracy and information content of ortho-images 
and DEM provided by the CartoSAT-1 Mission can be used for (a) 
updating topographical maps on 1:25,000 and 1:50,000 scales, (b) 
making fresh topographic maps at 1:25,000 scale, (c) Contouring 
at 10m interval and (d) generating thematic maps at 1:10,000 
scale. 
aide are ranging 
idard Deviation 
ed with SRTM 
iicates both are 
DEM, which is 
9m. Hence the 
; the specified 
applications of 
of CartoSAT-1 
5. 
‘y;?; 
h legend 
overlaid on the 
ire 6) and also 
DEM. 
Figure 6. Contours overlaid on DEM 
4.3 Planimetric accuracy of the ortho-image 
The ortho-mosaic for the entire study area is generated using the 
two aft-images and is depicted in Figure 7. The Planimetric 
accuracy of the ortho-image is validated at the checkpoints, 
provided by the PI and the corresponding CEP-90 measured is 
around 12m. This meets the specified accuracy. 
Figure 7. Ortho-mosaic of the study area 
5. CONCLUSIONS 
A series of orthorectification tests are carried out to evaluate the 
operational performance of the CartoSAT-1 sensor in the 
generation of ortho-images. The results show that it is 
comparatively straightforward to produce reliable products, well 
within the expected performance of a modem satellite instrument, 
from 2 to 3m RMSE 1-D (i.e. in either Northing or Easting 
directions). This is achieved using the RPC bias method (in LPS 
v9) using 14 GCP’s. The image quality, tested through 
radiometric and geometric characteristics of the CartoSAT-1 
stereo pairs also gave good results. 
Using the LPS method for sensor geometry modeling, the 
extraction of the corresponding DEM produced good results that 
are suitable for the operational use in planning and development 
REFERENCES AND SELECTED BIBLIOGRAPHY 
Cartosat-1 (IRS-P5) Data Products Generation Station: DDR 
Document. Signal and Image Processing Group, Space 
Applications Centre, Ahmedabad. April 2004. 
Kay, S., Spruyt P., and Alexandrou, K. (2003), Geometric quality 
assessment of orthorectified VHR space image data, 
Photogrammetric Engineering and Remote Sensing, May 2003, 
pp 484-491. 
Kay, S., Spruyt, P., Zielinski, R., Winkler, P., Mihaly, S., and 
Ivan G. (2005). Quality checking of DEM derived from satellite 
data (SPOT and SRTM). Global Developments in Environmental 
Earth Observation from Space, Proceedings of the 25th EARSeL 
Symposium, Porto, 6-11 June 2005, pp655 - 664 
Kay, S., R. Zielinski. 2006. Orthorectification And Geometric 
Quality Assessment Of Cartosat-1 For Common Agricultural 
Policy Monitoring. ISPRS Goa Congress, September 2006. 
NRSA (National Remote Sensing Agency) 2006. CARTOSAT-1 
Home page, http://www.nrsa.gov.in/cartosat-l/html/home.html 
PCI, 2006, Sensor model rectification technical data sheet, 
http://www.pcigeomatics.eom/pdfs/G 10%20Sensor%20Models.p 
df 
Rodriguez, E., Morris, C.S, and Belz, J.E., 2006, A Global 
Assessment of the SRTM Performance, Photogrammetric 
Engineering and Remote Sensing, March 2006, pp 249-260. 
Spruyt, P., Kay, S., 2004 Quality assessment test with Leica 
Geosystems ADS40: Digital Airborne Orthoimagery. 
GIMIntemational, June 2004, Vol. 18, Issue 6, pp. 35-37. 
Toutin, T. 2004. Review article: Geometric processing of remote 
sensing images: models, algorithms and methods. Int. J.Remote 
sensing, 20 May, 2004, Vol. 25, No. 10, 1893-1924. 
ACKNOWLEDGEMENTS 
First of all the authors would like to thank very much Dr. G. 
Madhavan Nair, Chairman, ISRO for permitting us to work in C- 
Sap programme. The authors would like to acknowledge Dr. P. K. 
Srivastava and Dr. R. Nandakumar for giving us an opportunity to 
participate in the C-SAP programme as Co-Investigators. The 
authors like to thank Simon Kay, the Principal Investigator of 
CSAP (TS-5) for sharing the reference DEM and Control network 
of the study area. Special Thanks are to ISRO scientists who 
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