, with the contents of four lines changed to
x1= nx-50 ; Leftmost grid point to depict, for dimension x or lon x2= nx ; Rightmost grid point to depict y1= ny-40 ; Lowermost grid point to depict, for dimension y or lat y2= ny ; Uppermost grid point to depict
in order to zoom in on a sub-domain.
The figure below was made by issuing the same command as in Example 1 and 2, after the file userdef.ncl was copied from