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Re: AI-GEOSTATS: Basic structure interpretation

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  • Brian R Gray
    Hi. I am ecologist, too. While I am not a geostatistician, I don t recall seeing strong arguments to suggest that some processes lead to one spatial model
    Message 1 of 1 , Mar 6, 2002
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      Hi. I am ecologist, too. While I am not a geostatistician, I don't recall
      seeing strong arguments to suggest that some processes lead to one spatial
      model rather than others. Of course, one might argue the other way
      around--that some models might indicate more or less covariance at, say,
      small separation distances. However, such an argument would likely--for
      ecologists at least--be specious because, given the size of the datasets we
      typically work with, such an argument would likely be based on impossibly
      small sample sizes. of course, such an argument would also be using the
      data to infer a hypothesis--a general no-no in traditional statistics. my
      two cents. cheers, brian

      ****************************************************************
      Brian Gray
      USGS Upper Midwest Environmental Sciences Center
      575 Lester Avenue, Onalaska, WI 54650
      ph 608-783-7550 ext 19, FAX 608-783-8058
      brgray@...
      *****************************************************************



      "nic-zac@liber
      o.it" <nic-zac To: ai-geostats@...
      Sent by: cc:
      ai-geostats-li Subject: AI-GEOSTATS: Basic structure interpretation
      st@...


      03/06/2002
      02:56 AM
      Please respond
      to
      "nic-zac@liber
      o.it"





      I'm re-posting my question becouse i've experienced some problems with
      my e-mail service.

      It's a newby question so sorry for bothering.

      After reading Goovaerts' Geostatistics for Natural Resources Evaluation
      and Isaaks and Srivastava's Applied Geostatistics I still haven't found
      a way to corectly choose among variogram models.

      Is a spherical model linked closer to a particular type of spatial
      process? Are continous and smooth processes better described by
      sphercial or and exponential model? Choosing between a sphericl or an
      exponetial model is just a matter of fitting to experimental variogram
      or is there specific reason on how the process under analysis works?

      As an ecologist I have to provide a "meaningful" explanation of why
      using a specific kind of model to describe my experimental variogram of
      an difference image of NDVI values derived from Landsat satellite.


      Any suggestion will be helpful.

      Thanks to all.

      NiCoLa

      ***********************************************************************
      *
      * Dott. Nicola Zaccarelli
      * Lab. di Ecologia del Paesaggio
      * Dip. di Scienze e Tecnologie Biologiche ed Ambientali
      * Università di Lecce
      *
      ***********************************************************************
      Prov.le Lecce-Monteroni
      73100 - LECCE

      Tel. (+39)- 0832-320.896
      Fax: (+39)- 0832-320.626
      e-mail: nicola.zaccarelli@...
      nic-zac@...


      NiCoLa
      ___________________________________________
      Dott. Nicola Zaccarelli
      C.N.R.-I.I.A.
      tel. 0832-320.886
      tel. 0832-320.896




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