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Re: GEOSTATS: cokriging in gslib

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  • Pierre Goovaerts
    Hello, Power models are not allowed for SIMPLE cokriging in the current version of cokb3d although they are allowed for simple kriging. Note that simple
    Message 1 of 4 , Dec 13, 1999
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      Hello,

      Power models are not allowed for SIMPLE cokriging
      in the current version of cokb3d although they
      are allowed for simple kriging.
      Note that simple (co)kriging systems need to be expressed in
      terms of covariances but pseudo-variances can be used
      to convert unbounded semivariograms into covariances.

      My advice is: Do not use simple cokriging since the
      assumptions of stationarity of the means are rarely met.
      Use the option ordinary cokriging and compare the
      two options: traditional and standardized cokriging since
      the unbiasedness constraints can influence the quality
      of the predictions, e.g. see
      Goovaerts, P. 1998. Ordinary cokriging revisited.
      Mathematical Geology, 30(1):21--42.

      Cheers,

      Pierre
      <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>

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      On Mon, 13 Dec 1999, Inge Frette wrote:

      > Hello folks,
      > not being an expert in geostatistics I wonder why the power model of the
      > variogram model
      > in Gslib is not allowed for when doing cokriging ?
      >
      > Anyone that knows why ?
      >
      > Regards from Inge Frette
      >
      >
      > ************************************************************************
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