GSLIB Help Page: IK3D
The program ik3d considers ordinary or simple indicator kriging
of either categorical and cdf-type indicators, it performs all order
relation corrections, and, optionally, allows the direct input of
already transformed indicator data, including possibly soft data and
A variogram is is required for each of the ncat
vartype: the variable type (1=continuous, 0=categorical)
ncat: the number of thresholds or categories
cat: the thresholds or categories (there should be ncat
values on this line of input)
pdf: the global cdf or pdf values (there should be ncat
values on this line of input)
datafl: the input continuous data in a simplified Geo-EAS
icolx, icoly, icolz, and icolvr: the columns for the x, y,
and z coordinates, and the continuous variable to be estimated.
directik: already transformed indicator values are read from
this file. Missing values are identified as less than tmin
which would correspond to a constraint interval. Otherwise, the cdf
data should steadily increase from 0 to 1 and soft categorical
probabilities must be between 0 to 1 and sum to 1.0.
icolx, icoly, icolz, and icoli: the columns for the x, y,
and z coordinates, and the indicator variables.
tmin and tmax: all values strictly less than tmin
and greater than or equal to tmax are ignored.
idbg: an integer debugging level between 0 and 3. The higher
the debugging level the more output.
dbgfl: the debugging output is written to this file.
outfl: the output grid is written to this file. The output
file will contain the order relation corrected conditional distributions
for all nodes in the grid. The conditional probabilities or ccdf
values will be written to the same
line or ``record''; there are ncat variables in the output
file. Unestimated nodes are identified by all ccdf values equal to
nx, xmn, xsiz: definition of the grid system (x axis).
ny, ymn, ysiz: definition of the grid system (y axis).
nz, zmn, zsiz: definition of the grid system (z axis).
ndmin and ndmax: the minimum and maximum number of data
points to use for kriging a block.
radius_hmax radius_hmin and radius_vert
the search radii in the maximum horizontal direction, minimum
horizontal direction, and vertical direction (see angles below).
sang1, sang2 and sang3: the angle parameters that
describe the orientation of the search ellipsoid. See the discussion
on anisotropy specification associated with Figure II.4.
noct: the maximum number of samples per octant (octant search
is not used if noct=0
mik and mikcut: If mik=0, then a full IK is performed.
If mik=1, then a median IK approximation is performed where the
kriging weights from the category or cutoff closest to mikcut
are used for all cutoffs.
ktype: simple kriging is performed if ktype=0 ordinary
kriging is performed if ktype=1
nst, and c0: the number of variogram structures
and the nugget constant, for the corresponding indicator variogram.
For each of the nst nested structures one must define it
the type of structure (the power model is not allowed);
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. A detailed
description of these parameters is given in section II.3.
A short description of the program