loc(x, y, angle=0, ratio=1)
y
.
Alternatively
x
can be a two column matrix containing both the
x and y locations.
x
.
angle
to
the anisotropy orthogonal to
angle
.
"loc"
containing the corrected spatial
locations.
The locations are corrected for geometric anisotropy by multipling each
location pair (
x[i]
,
y[i]
) by the symmetric 2 x 2 matrix
A
where
A[1,1]=
cos(angle)^2+
ratio*sin(angle)^2
,
A[1,2]=
(1- ratio)*
sin(angle)*
cos(angle)
and
A[2,2]=
sin(angle)^2+
ratio*cos(angle)^2
.
See Journel and Huijbregts (1978, pp 179-181).
Journel, A. G. and Huijbregts, Ch. J. (1978). Mining Geostatistics. Academic Press, New York.
variogram(ore ~ loc(easting, northing, angle=0, ratio=2), data=iron.ore)