1 October 2003
tion. The root mean square estimates the level of error in the transformation. The esti-
mate will not be calculated until three or four GCPs have been entered. Initial estimates
will be high, and should decrease as more GCPs are added to the image. A root mean
square below 1.0 is a reasonable level of accuracy. If the RMS is higher that 1.0, simply
reposition GCPs with high individual errors or delete them and reselect new GCPs. With
an error less than 1.0 the image is ready to be warped to the projection and saved.
a. The scene appearance of the GCP selection module may look
similar to this scene capture. Each segment of the function is
presented individually below.