## RE: AI-GEOSTATS: Variowin Maximal distance option

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• In Variowin Help appear In order to reduce the size of the pair comparison file, and hence the memory requirements of PREVAR2D and VARIO2DP, a Pair
Message 1 of 2 , Jan 23, 2002
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In Variowin Help appear

In order to reduce the size of the pair comparison file, and hence the
memory requirements of PREVAR2D and VARIO2DP, a Pair Comparison File can be
constructed from subsets of the available data :

1) Subsets can be based on maximum difference in X and/or Y coordinates
using the Settings | X and Y coordinates... menu item.
2) Subsets can be based on acceptable ranges of variables values using
the Settings | Limits... menu item.

In practice it is the same to not include in the analysis the lag that are
not in the range of maximum difference in X and/or Y.

The formula maximum lag = sqr(dx^2 + dy^2) is to rigid, in practice the
maximum lag depend of the objective of your work, some times the larges lag
give you interesting information for understand the behavior of the data. If
you pretend to utilize the variogram to estimate, refine shortest lags.

King regards

Ing. Geolólo (profesor)
Istituto Superior Minero Metalúrgico (ISMM)
Reparto Caribe.
Moa, Holguín, Cuba
CP 83329
E. Mail: amvargas@...

-----Mensaje original-----
De: Peter Bossew [mailto:p.bossew@...]
Enviado el: martes, 22 de enero de 2002 8:33
Para: ai-geostats@...
Asunto: AI-GEOSTATS: Variowin Maximal distance option

dear list,

I have a question on Variowin software. The 'Prevar2D' module (which is
used to create the pair files) has an option to select maximum differences
dx and dy in the x- and y-coordinates in order to reduce the number of
pairs (useful if there are too many data points, see Yves Pannatier's book
page 26).
I would expect that variograms calculated out of pair-files truncated this
way should have a maximum lag = sqr(dx^2 + dy^2). But in fact the
variograms go until the largest lag allowed by the range of the
coordinates.

But maybe I just did not understand the idea of the 'maximum distance'
option ?? (The manual does not say anything further about it.)

----------------------------------------------------------------------------
---------
Peter Bossew
Institute of Physics and Biophysics, University of Salzburg, Austria

home: Georg Sigl-Gasse 13/11, A-1090 Vienna, Austria
ph. +43-1-3177627, e-mail: p.bossew@...

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