I am trying to reproduce the results of the SpATS package using the mgcv package. More specifically, I am trying to obtain the adjusted means for the variable “gen” after correcting for
the spatial trend. The variables “row” and “col” are the coordinates of the plots in a rectangular grid. The plots are placed in the field in 3 adjacent blocks represented by the variable “rep”. Every “gen” is replicated at least once per block.