The instruction provided by Mathworks says this "geotiffwrite(filename,A,R) writes a georeferenced image or data grid, A, spatially referenced by R, into an output file, filename."
My question is what exactly is R?
I have a matrix Z the size of 181 x 361, and I want to save it as a Geotiff file so that my friend can read it into ArcGIS. I tried
geotiffwrite('a.tif', Z, size(Z))
and it did not work;