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[ai-geostats] Frightened of Spatial Autocorrelation

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  • Kevin M. Curtin
    Hello All, I m not sure if this is the correct forum for this.but a colleague has asked a question I d like to address. This fellow wants to predict the
    Message 1 of 10 , Sep 2, 2004
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      Hello All,

      I’m not sure if this is the correct forum for this…but a colleague has asked a question I’d like to address.

       

      This fellow wants to predict the location of archaeological sites based on factors such as soil type, proximity to a water source, slope, AND proximity to other archaeological sites.

       

      On proposing such a predictive model he has been challenged with, “How are you going to deal with Spatial Autocorrelation”. We’re not sure why SA should be a problem since we are suggesting that spatial proximity is a factor in settlement location.

       

      So, do we need to test for SA and why?

       

      Thanks in advance,

      Kevin

       

    • Koen Hufkens
      Some random remarks that went through my single braincell: I would focus on the physical environment to predict the locations, but it depends on what you call
      Message 2 of 10 , Sep 2, 2004
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        Some random remarks that went through my single braincell:

        I would focus on the physical environment to predict the locations, but
        it depends on what you call an archeological site.

        A part of the place where a settlement would be created, could be
        explained by the distance from the surrounding sites. But I would think
        of it as a marginal effect until pretty recent times.

        Why do I think this:

        - If you go way back, people where selfsubstaining living communities.
        So, if commerce wasn't that big a part of their life the distance to
        other villages wouldn't matter and the choices for starting a village
        would only be dominated by physical factors.

        - In recent times the distances could become more important because of
        trade and the fact that their were more people around, that would spread
        across the land to claim their part of a living community where there
        would be some "breathing" space. That "breathing" space could be your
        clue to finding more sites. But again only if the combination of the
        social factors (preventing overcrowding and the urge to claim your patch
        of land) and the biophysical ones were in favour of the people.

        No social pressure on a community = no need to resettle, bad land = no
        way someone is going to settle there (until recent times with better
        agricultural techniques).

        A case where your technique would work is a uniform type of soil and
        topography, where the (re-)settlement of people would only be dominated
        by social factors and not so much by biophysical ones. Look at maps of
        the champagne area in France (sorry, only example I could think of).

        So, depending on the timeframe your looking at my strategy would differ.
        On old settlements I wouldn't include the distance and focus more on
        detailed biophysical data like pollen data. For recent times the SA
        approach could be interesting, because of the social aspect, but I
        wouldn't let it dominate a prediction model. You could cross check it
        with a model without the distances and known sites with a leave one out
        methode to see how good it behaves. Anyway... have fun with it...

        Cheers,
        Koen.



        On Thu, 2004-09-02 at 21:43, Kevin M. Curtin wrote:
        > Hello All,
        >
        > I’m not sure if this is the correct forum for this…but a colleague has
        > asked a question I’d like to address.
        >
        >
        >
        > This fellow wants to predict the location of archaeological sites
        > based on factors such as soil type, proximity to a water source,
        > slope, AND proximity to other archaeological sites.
        >
        >
        >
        > On proposing such a predictive model he has been challenged with, “How
        > are you going to deal with Spatial Autocorrelation”. We’re not sure
        > why SA should be a problem since we are suggesting that spatial
        > proximity is a factor in settlement location.
        >
        >
        >
        > So, do we need to test for SA and why?
        >
        >
        >
        > Thanks in advance,
        >
        > Kevin
        >
        >
        >
        >
        >
        > ______________________________________________________________________
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      • Isobel Clark
        Kevin Sounds like an ideal case for Geographically Weighted Regression. You could use semi-variograms or spatial auto-correlation to determine exactly how
        Message 3 of 10 , Sep 2, 2004
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          Kevin

          Sounds like an ideal case for Geographically Weighted
          Regression.

          You could use semi-variograms or spatial
          auto-correlation to determine exactly how proximity
          defines relationship. My only current beef with GWR is
          the seemingly pre-defined distance weighting
          functions. Not had much time to get into this yet, so
          don't dump on me all you experts out there.

          I would be interested in any published results on this
          as one of my business partners is doing similar work
          on bronze age denmark.

          Isobel
          http://uk.geocities.com/drisobelclark





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        • Steven Citron-Pousty
          You might look at the following series of papers: http://www.nceas.ucsb.edu/~liebhold/ecography/ While the papers are written with an ecological focus,
          Message 4 of 10 , Sep 2, 2004
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            You might look at the following series of papers:
            http://www.nceas.ucsb.edu/~liebhold/ecography/
            While the papers are written with an ecological focus, settling is
            settling is settling.
            Hope they help...
            Steve

            Isobel Clark wrote:

            >Kevin
            >
            >Sounds like an ideal case for Geographically Weighted
            >Regression.
            >
            >You could use semi-variograms or spatial
            >auto-correlation to determine exactly how proximity
            >defines relationship. My only current beef with GWR is
            >the seemingly pre-defined distance weighting
            >functions. Not had much time to get into this yet, so
            >don't dump on me all you experts out there.
            >
            >I would be interested in any published results on this
            >as one of my business partners is doing similar work
            >on bronze age denmark.
            >
            >Isobel
            >http://uk.geocities.com/drisobelclark
            >
            >
            >
            >
            >
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            >
            >
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          • Beatrice Mare-Jones
            Hello Kevin You may like to speak to David Hansen a GIS Specialist/ Soil Scientist at the USGS in Sacramento - dhansen@mp.usbr.gov He has a good paper
            Message 5 of 10 , Sep 2, 2004
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              Hello Kevin

              You may like to speak to David Hansen a GIS Specialist/ Soil Scientist at
              the USGS in Sacramento - dhansen@...

              He has a good paper "Describing GIS Applications: Spatial Statistics and
              Weights of Evidence Extension to ArcView in the Analysis of the
              distribution of Archaeological Sites in Landscape. You may know this one -
              if not you can view it at www.goscafe.com?technical_papers/Papers/paper054

              Kind regards


              Beatrice





              "Kevin M. Curtin" <curtin@...>
              03/09/2004 07:43


              To: <ai-geostats@...>
              cc:
              Subject: [ai-geostats] Frightened of Spatial Autocorrelation


              Hello All,
              I'm not sure if this is the correct forum for this?but a colleague has
              asked a question I'd like to address.

              This fellow wants to predict the location of archaeological sites based on
              factors such as soil type, proximity to a water source, slope, AND
              proximity to other archaeological sites.

              On proposing such a predictive model he has been challenged with, "How are
              you going to deal with Spatial Autocorrelation". We're not sure why SA
              should be a problem since we are suggesting that spatial proximity is a
              factor in settlement location.

              So, do we need to test for SA and why?

              Thanks in advance,
              Kevin
              * By using the ai-geostats mailing list you agree to follow its rules
              ( see http://www.ai-geostats.org/help_ai-geostats.htm )

              * To unsubscribe to ai-geostats, send the following in the subject or in
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            • sebastiano
              I think that a fuzzy logic system approach is well suited for you task Some book where you can find something Principle of Geographical information Systems
              Message 6 of 10 , Sep 3, 2004
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                I think that a fuzzy logic system approach is well suited for you task
                Some book where you can find something "Principle of Geographical information Systems" Burrough and MCdonnel
                and "Fuzzy Logic in Geology", Demicco (2004)
                Bye
                Sebastiano trevisani
                 At 21.43 02/09/2004, you wrote:
                Hello All,
                I’m not sure if this is the correct forum for this…but a colleague has asked a question I’d like to address.
                 
                This fellow wants to predict the location of archaeological sites based on factors such as soil type, proximity to a water source, slope, AND proximity to other archaeological sites.
                 
                On proposing such a predictive model he has been challenged with, “How are you going to deal with Spatial Autocorrelation”. We’re not sure why SA should be a problem since we are suggesting that spatial proximity is a factor in settlement location.
                 
                So, do we need to test for SA and why?
                 
                Thanks in advance,
                Kevin
                 
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              • Viktoras Didziulis
                Hello, Kevin ! Predictive interpolation is a very interesting field. You may be interested in GIS applications based on Dempster-Shafer Theory. There are some
                Message 7 of 10 , Sep 3, 2004
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                  Hello, Kevin !

                  Predictive interpolation is a very interesting field.

                  You may be interested in GIS applications based on Dempster-Shafer Theory.
                  There are some online material also linked to archeology and prediction of
                  archaeological sites at http://gis.esri
                  com/library/userconf/proc99/proceed/papers/pap295/p295.htm
                  and http://websrv5.sdu.dk/ejstrud/forskning.html

                  Also IDRISI GIS has a collection of useful modeling tools for multicriteria
                  analysis. It is described in manual which can be downloaded from IDRISI web
                  site...

                  Another subject of interest might be various AI techniques. I personally am
                  experimenting with Case Based Reasoning (spatial predictions of community
                  structure). There are some references and an experimental module online at
                  http://www.alleco.fi/allmaps
                  Currently I am rewriting the code (for the third time already :)). Still, at
                  least for me it looks promising. Although currently I came to a decision
                  that these 'explicit' GIS modeling techniques must be suplemented with the
                  implicit' ones based on cellular automation, nearest neighbourhood or
                  variograms and krigging. The reason to think so is that those 'inteligent'
                  methods predict ecological niches. But in real world those niches may remain
                  unoccupied. So we need an interaction of explicit top-down influence in form
                  of 'niches' and implicit bottom-up influence in the form of 'growth from a
                  seed'.

                  Best regards
                  Viktoras

                  -------Original Message-------

                  From: Kevin M. Curtin
                  Date: 2004 m. rugs�jis 02 d. 12:44:03
                  To: ai-geostats@...
                  Subject: [ai-geostats] Frightened of Spatial Autocorrelation

                  Hello All,
                  I�m not sure if this is the correct forum for this�but a colleague has asked
                  a question I�d like to address.

                  This fellow wants to predict the location of archaeological sites based on
                  factors such as soil type, proximity to a water source, slope, AND proximity
                  to other archaeological sites.

                  On proposing such a predictive model he has been challenged with, �How are
                  you going to deal with Spatial Autocorrelation�. We�re not sure why SA
                  should be a problem since we are suggesting that spatial proximity is a
                  factor in settlement location.

                  So, do we need to test for SA and why?

                  Thanks in advance,
                  Kevin
                • Niels Chr. Nielsen
                  Isobel, Kevin and others I would be very interested as well, since my collegue (an archaeologist) and myself (geographer) are doing work on Bronze Age Denmark,
                  Message 8 of 10 , Sep 3, 2004
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                    Isobel, Kevin and others

                    I would be very interested as well, since my collegue (an archaeologist) and myself (geographer) are doing work on Bronze Age Denmark, in the landscape of Vendsyssel. See web site http://websrv5.sdu.dk/ejstrud/forskning.html
                    with paper http://websrv5.sdu.dk/ejstrud/forskning/GIS/ejstrud_wunsdorf_2001.pdf
                    and http://www.humaniora.sdu.dk/kulturmiljoe (mostly in Danish)

                    Niels


                    Isobel Clark wrote:
                    Kevin
                    
                    Sounds like an ideal case for Geographically Weighted
                    Regression. 
                    
                    You could use semi-variograms or spatial
                    auto-correlation to determine exactly how proximity
                    defines relationship. My only current beef with GWR is
                    the seemingly pre-defined distance weighting
                    functions. Not had much time to get into this yet, so
                    don't dump on me all you experts out there.
                    
                    I would be interested in any published results on this
                    as one of my business partners is doing similar work
                    on bronze age denmark.
                    
                    Isobel
                    http://uk.geocities.com/drisobelclark
                    
                    
                    	
                    	
                    		
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                    -- 
                    Niels Chr. Nielsen, M.Sc.
                    Skolevej 18, Nordby
                    DK-6720 Fanø
                    Tlf. (+45)76121216(evening),(+45)65504152(during day)
                    mobile (+45)20878568
                    e-mail: niels_c_nielsen@...
                    
                  • Rajive Ganguli
                    With ref. to the posting below (AI techniques and predictive work), we have recently done a lot of work comparing kriging and neural network performance. As
                    Message 9 of 10 , Sep 3, 2004
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                      With ref. to the posting below (AI techniques and predictive work), we
                      have recently done a lot of work comparing kriging and neural network
                      performance. As an example, one of those papers (soon to show up in
                      Jo. Exp. Geol) is posted at
                      http://www.faculty.uaf.edu/ffrg/papers/nomepap_modi_revise.zip.

                      To summarize our findings, I would say there hasn't been much
                      difference in prediction performance. One or the other is marginally
                      better on any given case. An indication of the absolute performance
                      of either methods can be easily obtained from the semi-variogram:
                      lower the nugget, better both methods perform, while higher the nugget
                      the worse they both perform.

                      In the paper that is posted, both methods performed very well with NN
                      having a prediction performance (R_sq) upwards of 0.98 with very low
                      bias and kriging being 0.95.

                      Thanks,


                      Rajive Ganguli, Ph.D., P.E., C.O.I
                      Associate Professor of Mining Engineering
                      University of Alaska Fairbanks
                      ================================
                      Office: 317 Duckering Building
                      Mailing Add: Box 755800, Fairbanks, AK 99775
                      ph: 907-474-7631, fax: 907-474-6635
                      web: http://www.faculty.uaf.edu/ffrg/
                      -------------------------------------------
                      "He uses statistics as a drunken man uses lamp-posts... for support rather
                      than illumination." - Andrew Lang (1844-1912)




                      -----Original Message-----
                      From: Viktoras Didziulis [mailto:viktoras.didziulis@...]
                      Sent: Friday, September 03, 2004 12:12 AM
                      To: ai-geostats@...
                      Subject: Re: [ai-geostats] Frightened of Spatial Autocorrelation

                      Hello, Kevin ! Predictive interpolation is a very interesting field. You
                      may be interested in GIS applications based on Dempster-Shafer Theory.
                      There are some online material also linked to archeology and prediction of
                      archaeological sites at http://gis.esri
                      com/library/userconf/proc99/proceed/papers/pap295/p295.htm and
                      http://websrv5.sdu.dk/ejstrud/forskning.html Also IDRISI GIS has a
                      collection of useful modeling tools for multicriteria
                      analysis. It is described in manual which can be downloaded from IDRISI web
                      site... Another subject of interest might be various AI techniques. I
                      personally am
                      experimenting with Case Based Reasoning (spatial predictions of community
                      structure). There are some references and an experimental module online at
                      http://www.alleco.fi/allmaps Currently I am rewriting the code (for the
                      third time already :)). Still, at
                      least for me it looks promising. Although currently I came to a decision
                      that these 'explicit' GIS modeling techniques must be suplemented with the
                      implicit' ones based on cellular automation, nearest neighbourhood or
                      variograms and krigging. The reason to think so is that those 'inteligent'
                      methods predict ecological niches. But in real world those niches may remain
                      unoccupied. So we need an interaction of explicit top-down influence in form
                      of 'niches' and implicit bottom-up influence in the form of 'growth from a
                      seed'. Best regards Viktoras -------Original Message------- From:
                      Kevin M. Curtin Date: 2004 m. rugsëjis 02 d. 12:44:03 To:
                      ai-geostats@... Subject: [ai-geostats] Frightened of Spatial
                      Autocorrelation Hello All, I'm not sure if this is the correct forum for
                      this…but a colleague has asked
                      a question I'd like to address. This fellow wants to predict the location
                      of archaeological sites based on
                      factors such as soil type, proximity to a water source, slope, AND proximity
                      to other archaeological sites. On proposing such a predictive model he has
                      been challenged with, "How are
                      you going to deal with Spatial Autocorrelation". We're not sure why SA
                      should be a problem since we are suggesting that spatial proximity is a
                      factor in settlement location. So, do we need to test for SA and why?
                      Thanks in advance, Kevin
                    • Volker Bahn
                      Hi Kevin, I work in the field of distribution modeling of birds and somewhat come from the other direction than most geostatistics people here on the list. In
                      Message 10 of 10 , Sep 7, 2004
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                        Hi Kevin,

                        I work in the field of distribution modeling of birds and somewhat come from
                        the other direction than most geostatistics people here on the list. In
                        ecology, we first only predicted by local conditions and habitat, then were
                        pointed to the problems of spatial autocorrelation in such an approach, then
                        tried to compensate for autocorrelation problems in statistics and only
                        lately recognized that autocorrelation is actually additional information
                        that could improve prediction. Steve already posted the most current papers
                        regarding this issue in Ecography, which helped me much
                        (http://www.nceas.ucsb.edu/~liebhold/ecography/). I would add the following
                        paper to the list:

                        Lichstein J. W., T. R. Simons, S. A. Shriner, and K. E. Franzreb. 2002.
                        Spatial autocorrelation and autoregressive models in ecology. Ecological
                        Monographs 72(3):445-463.

                        For birds it has been well documented that autocorrelation in distributions
                        are caused by autocorrelation in underlying resources. Thus, in theory, if
                        you cover ALL important predictors in your model (let's say a regular
                        regression or any other "non-spatial" method), the spatial structure in the
                        distribution is modeled implicitly by being contained in the predictors.
                        However, if you miss a predictor (which in practice will always be the
                        case), you will miss its spatial structure and the residuals of your
                        analysis will reflect this structure rendering these approaches ineffective
                        and statistically flawed. In addition, I'm trying to show in my research
                        that dispersal of individuals (meaning leaving either the birthplace or the
                        last breeding place permanently to breed elsewhere) also leads to
                        autocorrelation in distributions. This could also be the case for
                        archeological sites as there was undoubtedly some contact and exchange among
                        neighbors and this contact would have been more intense with close neighbors
                        as travel comes at a cost. Thus I would expect autocorrelation in the
                        spatial distribution of archeological sites above and beyond the
                        autocorrelation in the underlying conditions predicting archeological sites.
                        I use conditional autoregressive regression models (CAR) in Splus to model
                        bird distributions.

                        I hope this helps

                        Volker
                        _______________________________
                        Volker Bahn
                        Dept. of Wildlife Ecology - Rm. 210
                        University of Maine
                        5755 Nutting Hall
                        Orono, Maine
                        04469-5755, USA
                        Tel. (207) 581 2799
                        Fax: (207) 581 2858
                        volker.bahn@...
                        http://www.wle.umaine.edu/used_text%20files/Volker%20Bahn/home.htm


                        ----- Original Message -----
                        From: Kevin M. Curtin
                        To: ai-geostats@...
                        Sent: Thursday, September 02, 2004 15:43
                        Subject: [ai-geostats] Frightened of Spatial Autocorrelation


                        Hello All,
                        I'm not sure if this is the correct forum for this.but a colleague has asked
                        a question I'd like to address.

                        This fellow wants to predict the location of archaeological sites based on
                        factors such as soil type, proximity to a water source, slope, AND proximity
                        to other archaeological sites.

                        On proposing such a predictive model he has been challenged with, "How are
                        you going to deal with Spatial Autocorrelation". We're not sure why SA
                        should be a problem since we are suggesting that spatial proximity is a
                        factor in settlement location.

                        So, do we need to test for SA and why?

                        Thanks in advance,
                        Kevin




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