Converts wts data into the list form
high dimensional array with grid positions in the first two dimensions
List of Weights as a matrix (not list
like in R) as matrix or two dimensional array
One could describe this function as a transformation or a special case of wide to long format, see also ListAsEsomNeurons
Ultsch, A. Maps for the visualization of high-dimensional data spaces. in Proc. Workshop on Self organizing Maps. 2003.