GSLIB Help Page: BIGAUS
Description:
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This program allows checking for bivariate normality; a model of the
normal scores variogram is input to bigaus The corresponding
indicator semivariograms for specified cutoffs, lags, and directions
are output from the program. The idea is to see how far the
experimental indicator variograms deviate from those implied by the
bivariate Gaussian distribution. A numerical integration algorithm is
used to compute the Gaussian model-derived indicator variograms.
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Parameters:
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outfl: the output file for the theoretical Gaussian indicator
semivariograms. The format is the same as that created by the
gam program; therefore, the program vargplt could
be used to plot these indicator variograms.
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ncut: the number of thresholds.
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zc(ncut): ncut threshold values are required. These
thresholds are expressed in units of cumulative probability, e.g., the
lower quartile is 0.25, the median is 0.50. Note that the results are
symmetric: the variogram for the 5th percentile (0.05) is the
same as the 95th percentile (0.95).
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ndir and nlag: the number of directions and the number of
lags to be considered.
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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
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nst and c0: the number of structures and the nugget
effect.
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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.