Mosaic Tool can be used to reproject images to a different output projection (Edit --> Output Image Options tool --> Change Output Map Projection). When the difference between the desired output coordinate for a GCP and the actual transformed output coordinate for the same point exceeds the set tolerance level, errors will occur when creating the output mosaic similar to the messages below:
Image k:/img/0937/09371-1.img reprojection exceeds RMS tolerance. Increasing tolerance or or reprojecting image manually may prevent this message.
Image k:/img/0937/09371-2.img reprojection exceeds RMS tolerance. Increasing tolerance or or reprojecting image manually may prevent this message.
How can the tolerance setting be adjusted in Mosaic Tool to allow the mosaic process to run?
The RMS Tolerance setting can be adjusted in Mosaic Tool-->Toolbar-->Display Image Resample Options Dialog. The RMS Tolerance setting adjusts the allowable error tolerance (pixels) used in the image resampling. In other words, how many pixels off can a retransformed coordinate be, and still be correct and close enough to use? If the RMS Tolerance is 2, then the retransformed pixel can be 2 pixels away from the source pixel, and still be considered accurate. If the results are not accurate enough, lower the tolerance, but lowering the tolerance may make the process slower or not work at all.