## GSLIB Help Page: VMODEL

Description:

- 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.

Parameters:

- outfl: the output file that will contain the semivariogram values.
- 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 effect.
- 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 range.