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I am using QGIS 3.22 Stable version.

I'm trying to georeference two dat. files with Georeferencer plugin in the 'Raster' section of QGIS. I manually choose all the points using "tsunami_before" as base raster and the correspective points on "tsunami_after". I have chosen in the transformation setting the Thin Plate Spline as transformation type and the Nearest Neighbour as resambling method. When I start the georeferencing, the modified raster appears on my QGIS main screen, but on the georeferencer it doesn't show me the errors associated with every points (it gives me all zeros).

What is the possible reason for which the errors are null?

enter image description here

2 Answers 2

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It is because of this:

I have chosen in the transformation setting the Thin Plate Spline

https://mathworld.wolfram.com/ThinPlateSpline.html

Given a set of data points, a weighted combination of thin plate splines centered about each data point gives the interpolation function that passes through the points exactly while minimizing the so-called "bending energy."

Residuals cannot be used for evaluating the quality of TPS transformation because warped pixels always fit exactly with the ground control points. The other areas of the image may have however large distortions.

Change the transformation type to for example Polynomial 2 and you will see non-zero residuals.

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Using a different transformation setting it actually works, but my professor used Thin Plate Spline and the errors came out.

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