[ai-geostats] (kein Betreff)
- Dear list,
I´m new here and I hope my question is not too silly….
I want to create a variogram for my catena-data (1000m catena along a
valley with an “U” shape). For the silt content there is an expected
strong dependence with the reliefposition along the catena, which could
be described with a polynomal function and which I used for detrending.
So i used the residuals to calculate a directional variogram (direction
along the catena) with VARIOWIN for the silt content. The result:
besides the first lag, the semivariance is nearly constant after the
second lag and therewith the fitted variogram shows a very short range
and can be characterized by the following: Gamma(h): 2.64 + 8.098933
Sph.80.18067 (h), IGF: 1.6115e-02.
I also used VARIOWIN to create a variogram (same direction like before)
with the “raw” data without the detrending. And the result was - at
least for me – astonishing: there was a superb fitted variogram
Gamma(h): 0.3924 + 34.47 Sph.247.23 (h), IGF: 3.7351e-03 and no
indicator like a parabolic curve or anything that this variogram should
have a trend. Also astonishing for me: the range of 247,2 m was four
times longer than the 80,2 m of the first variogram!
Now I don´t know which variogram i should use.
Thank you in advance for answering,
Dipl.-Ing. Landeskultur und Umweltschutz Björn Koop
> > Institute of Land Use
> > University of Rostock
> > Justus-von-Liebig-Weg 6
> > D-18059 Rostock
> > Tel. +49 (0) 381-4982101
> > Fax. +49 (0) 381-4982159
> > bjoern.koop@...