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[ai-geostats] Re: Software for Automatic Semivariogram Estimation

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  • Isobel Clark
    Hi All It is difficult to have an automatic best fit semi-variogram until you define what you mean by best fit . Noel Cressie s goodness of fit statistic goes
    Message 1 of 3 , Feb 28, 2006
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      Hi All
       
      It is difficult to have an automatic best fit semi-variogram until you define what you mean by "best fit". Noel Cressie's goodness of fit statistic goes a long way towards the ideal, but is very insensitive to changes in nugget effect and pretty insensitive to fairly large changes in the ranges. Optimal Cressie fits aren't always optimal visually, either.
       
      None of the automated methods I've heard of will choose the type of semi-variogram model and/or the number of nested components. Or anisotropy for the most part.
       
      As Ed says, if we knew the criteria we'd all write software for it (and retire!).
       
      I also look forward to varied opinions. Semi-variogram fitting is one of the most subjective stages of a geostatistical analysis.
       
      Isobel 
      http://www.kriging.com
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