What is the approximate size of one pixel (in meters) on the SPOT image?
It is not obvious that the TM image has geometric distortion when comparing it to the already rectified SPOT image. Do not be fooled by appearances. With satellite imagery, it is almost never apparent from a glance that there is geometric or locational distortion. To assign a scale and coordinate system and remove geometric distortion from tmAtlanta, you need to find features on the image that correspond to well defined coordinates on SPOT image. These will be your Ground Control Points (GCPs). Ideally: (1) the features would be spread uniformly across the image to provide a clear indication of distortion in all directions; (2) there will be features located across topographic gradients to indicate variations in distortion associated with elevation; (3) there will at least twice as many GCPs as the minimum required for the correction algorithm (minimum requirements are 3 for linear interpolation, 6 for bilinear, and 10 for cubic); and (4) GCPs will be clearly demarcated on the image an
