Calculating the RMSE in Georeferencing in ArcGIS,

I couldn’t figure out how the ArcGIS calculates the RMSE while making the Georeferencing.

In principle, the RMSE can be seen as the average of errors of measured (calculated) values from their correct ones. Here, how the ArcGIS specify the correct values in order to calculate the RMSE?

Thank you

Best

Jamal

From the help file topic

I think you are confusing the term

correct,in statistics this would be a comparison between the RMS error between observed and predicted. In any event, if you switch around your observed and predicted values, you will still end up with the same RMS error, if you examine the equations.Also, when georeferencing, there is an underlying assumption that the map is "correct" and we are trying to get the image positioning "corrected". As we all know, that is not necessarily the case, because it excludes map error due either to errors in the maps creation, the use of outdated data (ie road alignments being moved) and a wide variety of things. In order to move forward and not dwell on these issues you have to assume something is correct. Otherwise, it would be very hard as a GIS practitioner to get through the day.