GSLIB Help Page: BACKTR
Description:
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Back transform normal scores values according to a table look up
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Parameters:
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datafl: a data file in simplified Geo-EAS format containing the
normal scores.
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ivr: the column number for the normal scores.
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tmin and tmax: all values strictly less than tmin
and strictly greater than tmax are ignored.
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outfl: the output file containing the back transformed values.
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transfl: an input file containing the transformation look-up
table, i.e., pairs of z and y values with z
being the original data values or class bound values and y
being the corresponding normal scores values. This is an input file
that corresponds to the table written out by nscore,
sgsim,
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zmin and zmax: are the minimum and maximum values to
be used for extrapolation in the tails.
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ltail and ltpar specify the back transformation
implementation in the lower tail of the distribution:
ltail=1 implements linear interpolation to
the lower limit zmin and ltail=2 implements power model
interpolation, with w=ltpar to the lower limit zmin
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Linear interpolation is used between known data values.
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utail and utpar specify the back transformation
implementation in the upper tail of the distribution:
utail=1 implements linear interpolation to the upper
limit zmax utail=2 power model interpolation,
with w=utpar to the upper limit zmax and
utail=4 implements hyperbolic model extrapolation to the
upper limit zmax with w = utpar