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1213Re: GEOSTATS: optimal sampling design

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  • Heinz Burger
    Mar 3, 1999
    • 0 Attachment
      GGP95RDS@... wrote:

      > Hello,
      >
      > Can anyone out there point me towards software I can use to calculate
      > the kriged estimation mean and kriged estimation variance so that I
      > generate graphs of number of observations within an isolated region
      > against standard error (as in McBratney and Webster 1983; Webster &
      > Oliver 1990: 272-282)?
      >
      > I want to use the kriged estimation variance to prescribe optimal
      > (soil) sampling designs for my study areas based on sampling on
      > regular rectangular grids.
      >
      > I have 8 data-sets for which I have modelled the experimental
      > variograms and have produced kriged contour map outputs using the
      > variogram parameterson Surfer 6.01. However, I cannot see any way of
      > calculating kriged variance and means using this software.

      Hello Richard,

      it is well known that SURFER don't handle kriging errors (yet). A simple
      trick
      for getting an error map: Take GEOEAS and transfer the output to
      Surfer. Use "nearest neigbour"-method for gridding with search-radius
      smaller than grid distance. This will reproduce exactly the kriging results
      - including errors.

      The other point is that you can't get the global estimation variance by this
      way.
      Since you have got data on a regular grid, you should use the "combination
      of elementary
      errors" (Journel & Huijbregts, Mining Geostatistics, Chapt. V.C).
      For irregular sample distribution see our on-line paper on "Geostatistics
      and the Polygonal
      Method" including a (German)VB3.0-program. (See my web-page: News).

      Good luck!

      Heinz Burger

      --
      *****************************************************
      Dr. Heinz Burger
      Freie Universitaet Berlin
      - Geoinformatik -
      Malteserstr. 74-100
      12249 BERLIN, Germany
      e-mail: hburger@...-berlin.de
      Web-Seite: http://userpage.fu-berlin.de/~hburger/hb/
      ****************************************************



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