GSLIB Help Page: VMODEL
This program will take the semivariogram model and write out a file
with the same format as the gam program so that it can be
plotted with vargplt The primary uses of vmodel are
to overlay a model on experimental points and also to provide a
utility to check the definition of the semivariogram model.
outfl: the output file that will contain the semivariogram
ndir and nlag: the number of directions and the number of
lags to be considered.
azm, dip and lag: for each of the ndir directions a
direction must be specified by azm and dip and a unit lag
offset must be specified (lag).
nst and c0: the number of structures and the nugget
For each of the nst nested structures one must define it,
the type of structure; cc, the c parameter;
ang1,ang2,ang3, the angles defining the geometric anisotropy;
aa_hmax, the maximum horizontal range; aa_hmin,
the minimum horizontal range; and aa_vert, the vertical