[ai-geostats] Re: kriging with trend
- OriolIf you can get a semi-variogram from the observations which does not contain a parabolic upturn (diagnostic of polynomial type trend) then your trend is weak enough to ignore.You can download a free tutorial on dealing with polynomial type trend at http://geoecosse.bzland.com/softwaresIsobel
Oriol Falivene <oriolfalivene@...> wrote:
Just a simple question...
I'm trying to produce a contour map from a structural surface. This
surface is highly non-stationary (actuaally dips towards NW)
I wolud like to know which could be the best solution for getting a
1) Fit a plyonomial surface to the sample values, which is used as a
drift. Substract the drift from the observations to get the residuals.
Estimate the variogram of the residuals (now the residual variable is
stationary). Perform OK on the residuals. Add the polynomial surface to
the residuals to get the interpolated surface.
2) Compute variograms from the observations. Use universal kriging to
get the interpolated surface.
tel. (+34) 93 4021373
fax (+34) 93 4021340
Fac. de Geologia,
Univ. de Barcelona
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