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AI-GEOSTATS: A question about "SASIM"

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  • 成仔
    Hello all members. I have a question about the subroutine SASIM in Gislib . I have 42 sample data and analysis it s spatial correction structure
    Message 1 of 2 , Jul 15, 2003
      Hello all members.
      I have a question about the subroutine "SASIM" in "Gislib".
      I have 42 sample data and analysis it's spatial correction structure (variogram) , then i use the information of it's histogram , variogram and indicator variogram into "SASIM" to generate several realizations.
      But the histogram of these realizations can't honor original sample data.
      Is any thing wrong in the procedure and is there any special techincque to adjust the parameter of "annealing schedule" ?
      Thank you for reading this message.
      Best Regards.

      Fan Cheng Cheng.
      National Chengkung University in Taiwan.
      E-mail: fan0929.cc01787@...




      [Non-text portions of this message have been removed]
    • Pierre Goovaerts
      Hello, First you have to see what is the perturbation mechanism used in the program: random swapping or random sampling of target histogram. In the first case,
      Message 2 of 2 , Jul 15, 2003
        Hello,

        First you have to see what is the perturbation mechanism used in the
        program: random swapping or random sampling of target histogram.
        In the first case, the initial image typically reproduces the
        target histogram and so it won't be affected by the pertubations.
        In the second case (which I believe is implemented in your
        version of sasim), poor reproduction of target histogram might indicate
        the need for increasing the relative weight assigned to this
        objective function component. Note that with only 42 observations
        both target histogram and semivariogram might not be highly reliable
        and deviations from these targets should be allowed.

        Regards,

        Pierre Goovaerts
        <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>

        Dr. Pierre Goovaerts
        President of PGeostat, LLC
        Chief Scientist with Biomedware Inc.
        710 Ridgemont Lane
        Ann Arbor, Michigan, 48103-1535, U.S.A.

        E-mail: goovaert@...
        Phone: (734) 668-9900
        Fax: (734) 668-7788
        http://alumni.engin.umich.edu/~goovaert/

        <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>

        On Tue, 15 Jul 2003, [big5] ¦¨¥J wrote:

        > Hello all members.
        > I have a question about the subroutine "SASIM" in "Gislib".
        > I have 42 sample data and analysis it's spatial correction structure (variogram) , then i use the information of it's histogram , variogram and indicator variogram into "SASIM" to generate several realizations.
        > But the histogram of these realizations can't honor original sample data.
        > Is any thing wrong in the procedure and is there any special techincque to adjust the parameter of "annealing schedule" ?
        > Thank you for reading this message.
        > Best Regards.
        >
        > Fan Cheng Cheng.
        > National Chengkung University in Taiwan.
        > E-mail: fan0929.cc01787@...
        >
        >
        >


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