Variogram modeling is usually a pre-requisite for
kriging and/or stochastic simulation. It's not 
usally something that you'd want to "automate" in some
sort of computer program. Selection of a model type/range/sill
will usually be based on available sample points,
or analagous samples of the same origin as the dataset
one is looking at, complemented by a qualitative interpretation
of the spatial model. I guess one can try to "program"
this whole process from start to finish (exploratory
data analysis/variogram modeling/kriging) but this is
not at all recommended. Perhaps in some applications with
abundant data, yes, but probably not in a geoscience
setting. 

You haven't told us what your applications are? Will you
be mapping some geological variable? Interpolating 6 million
pixels in an image file? Trying to gauge the distribution of a
certain species of rare tropical flower?

Syed

---- Original message ----
>Date: Mon, 8 Jul 2002 20:56:15 -0700
>From: "Eva Pierce" <[EMAIL PROTECTED]>
>Subject: AI-GEOSTATS: Optimal Kriging parameters
>To: <[EMAIL PROTECTED]>
>
>Hi. 
> 
>I want to use Ordinary Kriging on an arbitrary dataset of X,Y, and Z
>values to estimate the Z values on a grid of arbitrary size/density. But
>I don't know what length and scale parameters to choose for the
>semivariogram. So I need to answer the following questions. I'm looking
>for guidance and resources, not necessarily definitive answers. When
>answering, please keep in mind that I'm a computer programmer, not a
>statistician, by education and experience. :-)
> 
>1.     How does one measure the "goodness" or "badness" of a Kriging
>estimate? E.g. when the bounds of the grid are fairly close to the
>bounds of the dataset, I might expect the estimated surface of Z values
>to have roughly the same number of "bumps" and "valleys" as the original
>dataset (if discernible), and not too many flat regions. How do I
>quantify such characteristics, and are there others I should be looking
>for?
>2.     How does one arrive at the "optimal" length and scale parameters
>for the semivariogram when doing ordinary Kriging, given these measures
>of "goodness" and "badness"? (here's where my comp. sci education would
>come in handy, if I knew the answer to #1)
> 
>I'll send out a summary of answers that I receive. Thanks!
>Eva
> 
> 
> 
> 

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