Geometric correction error of SPOT5 remotely sensed image
Compared to aviation survey, the highresolution images of SPOT5 make it cost-efficient for remote sensing based land use mapping and land use dynamic monitoring at 1:10,000 scales, and the key technical problem is that whether the geometric correction error of the image is within the error limitation at this scale. In order to obtain the geometric correction precision and provide the precision reference for the applications of SPOT5 image to land use, one case study was taken in Nanxun (plain area) of Huzhou city. Based on the SPOT5 images acquired and the ground control points (GCPs) and check points taken by differential GPS through field survey, the error of self-correction and independentcorrection of images were analyzed. Besides X error, Y error and total RMS, other indices such as CE90 and CE95, maximal point position error, <3 m% and <5 m%, were used to evaluate the effects of different geometric correction models and different amount of GCPs to geometric correction. The best geometric correction results we got from SPOT5 images of plain area were X-2 m, Y-1.8 m, total RMS-2.8 m, maximal point position error-5.5 m, CE90-4.1 m, CE95-4.9 m, 75% of points’ position error <3 m and 98% of points’ position error <5 m. Based on the above results, a scheme for geometric correction of SPOT5 image was put forward.