DCL:GRPH2:UDPACK: Contour Routines: Explanation of Subroutines
Sets the value of the contour level used by udcntr (or udcntz) with an array giving the grid-point values and the step size or the approximate number of levels.
NumRu::DCL.udgclb(z,dx)
z, mx, nx, nySee udcntr (Section 8.2.1). dx See udgcla (Section 8.2.3)