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AI-GEOSTATS: Kriging a stream surface

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  • Maureen Walsh
    I am interested in using kriging to interpolate temperature surfaces for a stream that I work on, based on data from fixed point temperature loggers along the
    Message 1 of 4 , May 1, 2002
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      I am interested in using kriging to interpolate temperature surfaces for
      a stream that I work on, based on data from fixed point temperature
      loggers along the length of the stream. However, I am unsure if it is
      possible to constrain the analysis within the stream boundaries. I was
      wondering if anyone with experience conducting these types of analyses
      would have any suggestions about how to address this problem.
      Thank you very much,
      Maureen Walsh


      [Non-text portions of this message have been removed]
    • Warren Schlechte
      Maureen, I believe we met in Savannah a couple of years ago. If you don t mind, could you send me any responses you get as a summary? Such seems useful to
      Message 2 of 4 , May 2, 2002
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        Maureen,

        I believe we met in Savannah a couple of years ago. If you don't mind,
        could you send me any responses you get as a summary? Such seems useful to
        know - how to best deal with boundary conditions. It would seem from my
        neophyte position that such would be easy to do. First, you don't provide
        any data from the adjacent land. Hence the estimation of the variogram won't
        take anything but stream readings into account. Second, when you provide a
        grid to estimate over, only provide points that lay within the stream. One
        item you will want to consider is how you portray your grid. Since a stream
        is a self-contained entity, I would think that distance should be portrayed
        as distance within the stream, distance as the water flows, not distance as
        the crow flies. Another aspect you may wish to consider is that streams
        have direction. Hence, it would seem unusual (with the exception of large
        inflows) for downstream sites to ever have an effect on upstream sites.
        This would suggest all sites should only look upstream for temperature
        information. The final item that comes to mind quickly is the influence of
        inflow. These will be sources of different temperatures than exist in the
        main stream basin. As such, it would seem that any major inflows should be
        measured.

        Hope that my thought help, and that you get the help you need from this
        group.


        Warren Schlechte

        -----Original Message-----
        From: ai-geostats-list@... [mailto:ai-geostats-list@...] On Behalf
        Of Maureen Walsh
        Sent: Wednesday, May 01, 2002 9:35 PM
        To: ai-geostats@...
        Subject: AI-GEOSTATS: Kriging a stream surface

        << File: vcard.vcf >> I am interested in using kriging to interpolate
        temperature surfaces for
        a stream that I work on, based on data from fixed point temperature
        loggers along the length of the stream. However, I am unsure if it is
        possible to constrain the analysis within the stream boundaries. I was
        wondering if anyone with experience conducting these types of analyses
        would have any suggestions about how to address this problem.
        Thank you very much,
        Maureen Walsh


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      • William Thayer
        To expand on one of the points that Mr Schlechte made regarding measuring distance along the stream, I suggest you get a copy of Pierre Goovaerts publication
        Message 3 of 4 , May 2, 2002
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          To expand on one of the points that Mr Schlechte made regarding measuring
          distance along the stream, I suggest you get a copy of Pierre Goovaerts
          publication from ES&T. Unfortunately, I don't have the citation but the
          subject was applying geostatistics to the Passaic (?) River in NJ and it
          was published in 2001 or 2002. The paper addresses transforming
          coordinates to account for stream meandering.
          Bill

          At 08:37 AM 5/2/02 -0500, Warren Schlechte wrote:
          >Maureen,
          >
          >I believe we met in Savannah a couple of years ago. If you don't mind,
          >could you send me any responses you get as a summary? Such seems useful to
          >know - how to best deal with boundary conditions. It would seem from my
          >neophyte position that such would be easy to do. First, you don't provide
          >any data from the adjacent land. Hence the estimation of the variogram won't
          >take anything but stream readings into account. Second, when you provide a
          >grid to estimate over, only provide points that lay within the stream. One
          >item you will want to consider is how you portray your grid. Since a stream
          >is a self-contained entity, I would think that distance should be portrayed
          >as distance within the stream, distance as the water flows, not distance as
          >the crow flies. Another aspect you may wish to consider is that streams
          >have direction. Hence, it would seem unusual (with the exception of large
          >inflows) for downstream sites to ever have an effect on upstream sites.
          >This would suggest all sites should only look upstream for temperature
          >information. The final item that comes to mind quickly is the influence of
          >inflow. These will be sources of different temperatures than exist in the
          >main stream basin. As such, it would seem that any major inflows should be
          >measured.
          >
          >Hope that my thought help, and that you get the help you need from this
          >group.
          >
          >
          >Warren Schlechte
          >
          > -----Original Message-----
          >From: ai-geostats-list@... [mailto:ai-geostats-list@...] On Behalf
          >Of Maureen Walsh
          >Sent: Wednesday, May 01, 2002 9:35 PM
          >To: ai-geostats@...
          >Subject: AI-GEOSTATS: Kriging a stream surface
          >
          > << File: vcard.vcf >> I am interested in using kriging to interpolate
          >temperature surfaces for
          >a stream that I work on, based on data from fixed point temperature
          >loggers along the length of the stream. However, I am unsure if it is
          >possible to constrain the analysis within the stream boundaries. I was
          >wondering if anyone with experience conducting these types of analyses
          >would have any suggestions about how to address this problem.
          >Thank you very much,
          >Maureen Walsh
          >
          >
          >--
          >* To post a message to the list, send it to ai-geostats@...
          >* As a general service to the users, please remember to post a summary of
          >any useful responses to your questions.
          >* To unsubscribe, send an email to majordomo@... with no subject and
          >"unsubscribe ai-geostats" followed by "end" on the next line in the message
          >body. DO NOT SEND Subscribe/Unsubscribe requests to the list
          >* Support to the list is provided at http://www.ai-geostats.org

          **************************************************
          William C. Thayer, P.E.

          Environmental Science Center
          Syracuse Research Corporation
          301 Plainfield Road, Suite 350
          Syracuse, NY 13212
          phone: (315) 452-8424
          fax: (315) 452-8440
          email: thayer@...
          web: http://esc.syrres.com/
          http://esc.syrres.com/geosem/
          **************************************************



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        • Noemi Barabas
          Dear Maureen, I have dealt with the same problem. The basic approach is to transform your coordinates as Warren suggested. If you only have one measurement
          Message 4 of 4 , May 2, 2002
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            Dear Maureen,

            I have dealt with the same problem. The basic approach is to transform
            your coordinates as Warren suggested. If you only have one measurement
            per transect, than it is as simple as working with distance from a set
            point such as the last or first sampling point, and your variogram and
            kriging is one-dimensional. If you need a 2-dimensional transformation,
            than it gets much more complicated. There are different approaches
            possible, such as normalizing to distance from one bank or from the
            center of flow. Then, regardless of how wide the stream is, two points
            1/3 of the way into the stream will have the same lateral coordinates. You
            also have to account for angles to the bank or center line.

            I used a grid generation approach in my case. You can use commercial
            software or write your own code. I settled for the latter, the commercial
            software (Gridgen from Pointwise) is for much more complicated problems.

            Look at this reference for a general description:
            Barabas N, Goovaerts P, Adriaens P (2001) Geostatistical Assessment and
            Validation of Uncertainty for Three-Dimensional Dioxin Data from Seidments
            in an Estuarine River. Environ. Sci. Technol. 35, 3294-3301.

            Noemi
            Noemi Barabas

            PhD Candidate
            The University of Michigan
            Dept. Civil and Environmental Engineering
            1351 Beal Avenue (13 EWRE)
            Ann Arbor, MI 48109-2125
            Phone: (734) 615-5905


            On Thu, 2 May 2002, Warren Schlechte wrote:

            > Maureen,
            >
            > I believe we met in Savannah a couple of years ago. If you don't mind,
            > could you send me any responses you get as a summary? Such seems useful to
            > know - how to best deal with boundary conditions. It would seem from my
            > neophyte position that such would be easy to do. First, you don't provide
            > any data from the adjacent land. Hence the estimation of the variogram won't
            > take anything but stream readings into account. Second, when you provide a
            > grid to estimate over, only provide points that lay within the stream. One
            > item you will want to consider is how you portray your grid. Since a stream
            > is a self-contained entity, I would think that distance should be portrayed
            > as distance within the stream, distance as the water flows, not distance as
            > the crow flies. Another aspect you may wish to consider is that streams
            > have direction. Hence, it would seem unusual (with the exception of large
            > inflows) for downstream sites to ever have an effect on upstream sites.
            > This would suggest all sites should only look upstream for temperature
            > information. The final item that comes to mind quickly is the influence of
            > inflow. These will be sources of different temperatures than exist in the
            > main stream basin. As such, it would seem that any major inflows should be
            > measured.
            >
            > Hope that my thought help, and that you get the help you need from this
            > group.
            >
            >
            > Warren Schlechte
            >
            > -----Original Message-----
            > From: ai-geostats-list@... [mailto:ai-geostats-list@...] On Behalf
            > Of Maureen Walsh
            > Sent: Wednesday, May 01, 2002 9:35 PM
            > To: ai-geostats@...
            > Subject: AI-GEOSTATS: Kriging a stream surface
            >
            > << File: vcard.vcf >> I am interested in using kriging to interpolate
            > temperature surfaces for
            > a stream that I work on, based on data from fixed point temperature
            > loggers along the length of the stream. However, I am unsure if it is
            > possible to constrain the analysis within the stream boundaries. I was
            > wondering if anyone with experience conducting these types of analyses
            > would have any suggestions about how to address this problem.
            > Thank you very much,
            > Maureen Walsh
            >
            >
            > --
            > * To post a message to the list, send it to ai-geostats@...
            > * As a general service to the users, please remember to post a summary of any useful responses to your questions.
            > * To unsubscribe, send an email to majordomo@... with no subject and "unsubscribe ai-geostats" followed by "end" on the next line in the message body. DO NOT SEND Subscribe/Unsubscribe requests to the list
            > * Support to the list is provided at http://www.ai-geostats.org
            >


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