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AI-GEOSTATS: Estimation of the cross semivariogram

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  • Soeren Nymand Lophaven
    Dear list I have a question regarding estimation of the cross semivariogram, given by: gamma(h)=1/2N(h)*sum((z_i-z_j)(y_i-y_j)) where y and z are the two
    Message 1 of 2 , Feb 14, 2003
      Dear list

      I have a question regarding estimation of the cross semivariogram,
      given by:

      gamma(h)=1/2N(h)*sum((z_i-z_j)(y_i-y_j))

      where y and z are the two variables. My question simply is: Do y and z
      have to be measured at the same locations in order to estimate the cross
      semivariogram ??

      Best regards / Venlig hilsen

      Søren Lophaven
      ******************************************************************************
      Master of Science in Engineering | Ph.D. student
      Informatics and Mathematical Modelling | Building 321, Room 011
      Technical University of Denmark | 2800 kgs. Lyngby, Denmark
      E-mail: snl@... | http://www.imm.dtu.dk/~snl
      Telephone: +45 45253419 |
      ******************************************************************************


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    • Isobel Clark
      Soeren What you have here is sometimes known as a co-located cross semi-variogram and only pairs of samples with both variables can be included in its
      Message 2 of 2 , Feb 14, 2003
        Soeren

        What you have here is sometimes known as a co-located
        cross semi-variogram and only pairs of samples with
        both variables can be included in its calculation.

        There is a non-co-located semi-variogram (see
        Cressie's book for example) which looks like

        gamma(h)=1/2N(h)*sum((z_i-y_j^2)

        This works best if the variables are standardised
        (same mean, same standard deviation) and uses all of
        the samples with either variable.

        Isobel Clark
        http://geoecosse.bizland.com/news.html


        --- Soeren Nymand Lophaven <snl@...> wrote: >
        Dear list
        >
        > I have a question regarding estimation of the cross
        > semivariogram,
        > given by:
        >
        > gamma(h)=1/2N(h)*sum((z_i-z_j)(y_i-y_j))
        >
        > where y and z are the two variables. My question
        > simply is: Do y and z
        > have to be measured at the same locations in order
        > to estimate the cross
        > semivariogram ??
        >
        > Best regards / Venlig hilsen
        >
        > Søren Lophaven
        >
        ******************************************************************************
        > Master of Science in Engineering | Ph.D.
        > student
        > Informatics and Mathematical Modelling | Building
        > 321, Room 011
        > Technical University of Denmark | 2800 kgs.
        > Lyngby, Denmark
        > E-mail: snl@... |
        > http://www.imm.dtu.dk/~snl
        > Telephone: +45 45253419 |
        >
        ******************************************************************************
        >
        >
        > --
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