XYZtoMatrix

I am having an issue when using XYZtoMatrix. I have and X, Y, X data set which is complete (i.e. doesn't require interpolation) and I just want to put it in a grid however when I use the XYZtoMatrix it does not seem to scale correctly. Not sure what I am doing wrong. Thanks for any help. Matthew

johnweeks

Your XYZ triplets are in an unusual order- they describe a serpentine pattern rather than a raster scan. That is, the X values start low and go up, then from there start high and go down, etc. The usual way to make gridded XYZ triplets into a matrix is simply to redimension the Z values into the appropriately dimensioned matrix. For your data (a 25x25 matrix):


•Duplicate/O zwave, matrix2
•redimension/N=(25,25) matrix2

Now every other column is in the reverse order. So I wrote this little function to reverse the order of every other column:


Function ReverseOddColumns(Wave w)
	Variable nrows = DimSize(w, 0)
	Variable ncols = DimSize(w, 1)
	Make/N=(nrows)/FREE temp
	Variable i
	for (i = 1; i < ncols; i+=2)
		temp = w[p][i]
		w[][i] = temp[nrows-p-1]
	endfor
end

Invoke the function on our matrix:


•ReverseOddColumns(matrix2)

To reflect the increment in X and Y values, set the scaling of the matrix:


•SetScale/I y 1.25, -1.25, matrix2
•SetScale/I x -1.25, 1.25, matrix2

Note that the Y scaling is reversed, to reflect another oddity of your data set: the Y values start high and go down. We could reverse the order of the columns instead, if that were advantageous.

John Weeks
WaveMetrics, Inc.
support@wavemetrics.com

June 5, 2018 at 10:00 am - Permalink

mlm198

Thanks. I thought the odd data collection order might have been the issue. Matthew

June 8, 2018 at 12:55 am - Permalink