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[ai-geostats] Re: the sum of the simple kriging weights

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  • Isobel Clark
    Andreas The simple kriging weights are not constrained in any way, either in sum or in sign. Solving the simple kriging system gives a regression equation
    Message 1 of 1 , Jan 4, 2005
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      Andreas

      The simple kriging weights are not constrained in any
      way, either in sum or in sign.

      Solving the simple kriging system gives a regression
      equation which 'best' predicts the value at the
      specified location. This is usually adjusted to be
      unbiassed by applying the 'rest' (1 - sum of weights)
      to the global average.

      I have had cases where the simple kriging weights
      added up to 2.

      Isobel
      http://geoecosse.bizland.com



      --- Andreas Dominik Cullmann <acullma@...> wrote:

      > Hi all,
      > the simple kriging weights do not sum to a constant.
      >
      >
      > From Olea (1999): 'Geostatistics for engineers and
      > earth scientists',
      > Kluwer, Boston, p.60:
      > '(c) The possibility of having negative weights
      > implies that the
      > estimate is not confined to the data interval;...'
      >
      > To me, this sounds like if the sum of the simple
      > kriging weights
      > is resticted to some interval, especially since I've
      > never seen
      > any sum of weights not in [0,1].
      > Does anybody know any hint, evidence or proof of
      > such a
      > restriction?
      >
      > Thanks a lot.
      >
      >
      > ---------------------------------
      > Andreas Dominik Cullmann
      > Institut fuer forstliche Biometrie und Informatik
      > Buesgenweg 4
      > 37077 Goettingen
      > Germany
      > Tel: ++49-551-39-3462
      >
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