I am after the same solution to Removing elevation trend over sloped surfaces?
I am following the steps outlined, but in the last step it states:
In this expression [X'] refers to the the x-coordinate grid in the original coordinates and [Y'] refers to the original y-coordinate grid.
I'm not sure what is meant by the original coordinate grids. It doesn't look as if these are the original x and y values.
What are the coordinate grid values, and how I might obtain them?
That Q&A is quite old so perhaps there is a new method for carrying out this operation.