The input data set must
contain at least three numeric variables:
-
two horizontal variables (
x,
y)
-
one or more vertical variables,
z through
z-
n, that is interpolated or
smoothed as if it were a function of the two horizontal variables
The G3GRID procedure
can process multiple vertical variables for each pair of horizontal
variables that you specify:
-
if you specify more than one vertical
variable, the G3GRID procedure performs a separate analysis, and produces
interpolated or smoothed values for each vertical variable
-
if more than one observation in
the input data set has the same values for both horizontal variables,
x and
y, only the first observation is used in the interpolation. A warning
message is printed to the log.
-
by default, the interpolation is
performed after both variables are similarly scaled, because the interpolation
methods assume that the scales of
x and
y are comparable
