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GEOSTATS: Indicator Variograms

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  • Steve Friedman
    I m new to this list, but it was recommended to me as the place to seek geostatistical assistance, so here goes. I m working with a very large regional
    Message 1 of 3 , Mar 10, 1998
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      I'm new to this list, but it was recommended to me as the place to seek
      geostatistical assistance, so here goes.

      I'm working with a very large regional analysis of presettlement vegetation
      patterns using General Land Office records. This data set is a point base
      system. Each point consists of from 1 - 4 entries for a tree species present
      at that location, absence data is not included in the data collection process.

      I'd like to model the presence of each species using indicator variograms for
      comparisons between the species and secondly to compare results from
      spatial autocorrelation for nominal data.

      My questions:
      1. Where can I find software applications for indicator variograms?

      2. What is the relationship between indicator variograms and nominal
      spatial autocorrelation? My assumption is that the techniques should
      produce similar results. Am I correct?


      If anyone knows of literature contrasting these techniques I'd certainly
      appreciate learning about that as well.

      Sincerely.


      *********************************
      Steve Friedman email friedman@...
      Dept. Forest Resources
      University of Minnesota
      St. Paul, Minnesota 55108

      *********************************

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    • Yoshiro Nagao
      My problem seems to be same with the captioned one: We collected several insect species(A,B,C,D...) at sampling locations. Species A and B are negatively
      Message 2 of 3 , Apr 14, 1998
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        My problem seems to be same with the captioned one:

        We collected several insect species(A,B,C,D...) at sampling locations.

        Species A and B are negatively correlated in number at each the location.

        However, when I make a interpolated picture by inverse distance weighting,
        the density picture for A and B are nearly similar and are overlapped.
        ( I made the programme.)

        I concluded that species A and B are in competition in micro habitat,
        but their macro habitat are rather same.

        Actually A and B are near on their phylogenic tree.

        How can I geo-statistically show such a scale dependent
        spatial correlation?

        "Variogram" is the suitable method?

        It would be appreciated if a good book on this matter is
        recommended.

        "Steve Friedman" <friedman@...> sama said:
        >I'm working with a very large regional analysis of presettlement vegetation
        >patterns using General Land Office records. This data set is a point base
        >system. Each point consists of from 1 - 4 entries for a tree species present
        >at that location, absence data is not included in the data collection process.
        >
        >I'd like to model the presence of each species using indicator variograms for
        >comparisons between the species and secondly to compare results from
        >spatial autocorrelation for nominal data.
        >
        >My questions:
        >1. Where can I find software applications for indicator variograms?
        >
        >2. What is the relationship between indicator variograms and nominal
        > spatial autocorrelation? My assumption is that the techniques should
        > produce similar results. Am I correct?

        Nagao Yoshiro
        International Centre for Medical Research
        Kobe University
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      • Pierre Goovaerts
        Indicator semivariograms are indeed the perfect tools for detecting the presence of scale-dependent correlations between categories. A good reference for
        Message 3 of 3 , Apr 15, 1998
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          Indicator semivariograms are indeed the perfect tools for
          detecting the presence of scale-dependent correlations
          between categories.
          A good reference for application of geostat structural tools
          to ecological data is:
          Rossi RE, Mulla DJ, Journel AG, Franz EH (1992) Geostatistical
          tools for modeling and interpreting ecological spatial dependence.
          Ecol. Monogr. 62: 277-314


          Regarding the general issue of scale-dependent correlations,
          you can take a look at the following references:
          - Goovaerts P, Webster R (1994) Scale-dependent correlation
          between topsoil copper and cobalt concentrations in Scotland.
          Eur. J. Soil Sci. 45: 79--95
          - Goovaerts P (1997) Geostatistics for natural resources evaluation.
          Oxford Univ. Press, New-York, 483 pp.



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

          ________ ________
          | \ / | Pierre Goovaerts
          |_ \ / _| Assistant professor
          __|________\/________|__ Dept of Civil & Environmental Engineering
          | | The University of Michigan
          | M I C H I G A N | EWRE Building, Room 117
          |________________________| Ann Arbor, Michigan, 48109-2125, U.S.A
          _| |_\ /_| |_
          | |\ /| | E-mail: goovaert@...
          |________| \/ |________| Phone: (734) 936-0141
          Fax: (734) 763-2275

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


          On Wed, 15 Apr 1998, Yoshiro Nagao wrote:

          > My problem seems to be same with the captioned one:
          >
          > We collected several insect species(A,B,C,D...) at sampling locations.
          >
          > Species A and B are negatively correlated in number at each the location.
          >
          > However, when I make a interpolated picture by inverse distance weighting,
          > the density picture for A and B are nearly similar and are overlapped.
          > ( I made the programme.)
          >
          > I concluded that species A and B are in competition in micro habitat,
          > but their macro habitat are rather same.
          >
          > Actually A and B are near on their phylogenic tree.
          >
          > How can I geo-statistically show such a scale dependent
          > spatial correlation?
          >
          > "Variogram" is the suitable method?
          >
          > It would be appreciated if a good book on this matter is
          > recommended.
          >
          > "Steve Friedman" <friedman@...> sama said:
          > >I'm working with a very large regional analysis of presettlement vegetation
          > >patterns using General Land Office records. This data set is a point base
          > >system. Each point consists of from 1 - 4 entries for a tree species present
          > >at that location, absence data is not included in the data collection process.
          > >
          > >I'd like to model the presence of each species using indicator variograms for
          > >comparisons between the species and secondly to compare results from
          > >spatial autocorrelation for nominal data.
          > >
          > >My questions:
          > >1. Where can I find software applications for indicator variograms?
          > >
          > >2. What is the relationship between indicator variograms and nominal
          > > spatial autocorrelation? My assumption is that the techniques should
          > > produce similar results. Am I correct?
          >
          > Nagao Yoshiro
          > International Centre for Medical Research
          > Kobe University
          > --
          > *To post a message to the list, send it to ai-geostats@....
          > *As a general service to list users, please remember to post a summary
          > of any useful responses to your questions.
          > *To unsubscribe, send email to majordomo@... with no subject and
          > "unsubscribe ai-geostats" in the message body.
          > DO NOT SEND Subscribe/Unsubscribe requests to the list!
          >

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