Rates of river channel migration or widening are only valid if it can be demonstrated that the amount of change in the measured parameters exceeds the measurement errors. However, it is still uncommon to see estimates of errors presented alongside rates of river channel change measured from aerial photography. Here, detailed methods are presented for the estimation of errors in quantifying channel migration rates that can be easily applied to GIS-based analysis of planform change. In addition, the impact of relaxing assumptions regarding error independence between image dates and systematic registration errors is presented and discussed. Copyright Â© 2005 John Wiley & Sons, Ltd.