Relative Accuracy of Rectifications Using
Coordinates Determined from Maps and the
Global Positioning System
Allen E. Cook and John E. Pinder III
Global positioning systems (GPS) that use code phase receivers have the potential
for providing more accurate coordinates for ground control points (GCPS) than
do 7.5-minute quadrangle maps. To evaluate the effect of the greater accuracy of
GPS in determining coordinates for satellite image,,, GGP coordinates were
measured on maps and by Gps techniques and were then used to rectify Landsat
Thematic Mapper, SPOT multispectral, and SPOT panchromatic images from the
same area. There were major differences between rectifications using map and
Gps coordinates. For Thematic Mapper data, 24 percent of the values assigned to
pixels in the rectification performed using map coordinates differed from the values
assigned to the same pixels in the rectification performed using the GPS
coordinates. For SPOT multispectral and SPOT panchromatic images, the
percentage of pixels with different assignments were greater than 40 percent. The
improvements in accuracy when using the GPS data were substantial for even the
relatively large Thematic Mapper pixels and warrant the use of GPS where
position accuracy is essential.
SREL Reprint #2006
Cook, A.E. and J.E. Pinder, III. 1996. Relative accuracy of rectifications using
coordinates determined from maps and the global positioning system.
Photogrammetric Engineering and Remote Sensing 62:73-77.
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