Loading ...
Sorry, an error occurred while loading the content.

AI-GEOSTATS: TIN-ACCURANCY2

Expand Messages
  • Ines
    dear list I must generate a DEM using the TIN interpolator, using geostatistical analyst extension of ArcGis software can I define the DEM accurancy (raster
    Message 1 of 2 , Jan 28, 2004
    • 0 Attachment
      dear list

      I must generate a DEM using the TIN interpolator, using geostatistical analyst extension of ArcGis software can I define the DEM accurancy (raster output not only thr RMS error) like I do with the kriging interpolator?
      if it is not possible tell me a method to do this,which software can I use?

      thank you for your availability

      Ines

      ps. I have lost the last e-mail because of virus


      [Non-text portions of this message have been removed]
    • bob sandefur
      Hi- No one responded as of 1500 on 28 Jan so a few ideas: I assume you have irregular data and are using a TIN to generate a grid. Since a point in a TIN
      Message 2 of 2 , Jan 28, 2004
      • 0 Attachment
        Hi-

        No one responded as of 1500 on 28 Jan so a few ideas:

        I assume you have irregular data and are using a TIN to generate a grid.
        Since a point in a TIN triangle is a linear combination of the 3 points the
        linear estimation variance using the variogram of the TIN X Y Z points and
        weights should work as error estimator.
        Possible pit falls
        1.) If you are modeling topography it is often non covariance stationary.
        2.) If the xyz data are contour lines you should honor the contours when you
        TIN.
        3.) Three points are probably less than optimal for min estimation variance.

        A cross validation where you drop out a point, TIN with nearby data and read
        the z at the x y of the thrown out point and compare to actual z at that
        point should also work if the data isn't on contour lines. (and cross
        validation isn't too hard or time consuming in arcGis).

        Hope this helps

        Robert (Bob) L. Sandefur PE
        Senior Geostatistician / Reserve Analyst
        CAM
        200 Union Suite G-13
        Lakewood, Co
        80228

        rsandefur@...

        303 472-3240 (cell) <-best choice

        303 716-1617 ext 14



        -----Original Message-----
        From: ai-geostats-list@... [mailto:ai-geostats-list@...]On Behalf Of
        Ines
        Sent: Tuesday, January 27, 2004 3:20 AM
        To: ai-geostats@...
        Subject: AI-GEOSTATS: request - accurancy TIN


        dear list

        I must generate a DEM using the TIN interpolator, using geostatistical
        analyst extension of ArcGis software can I define the DEM accurancy (raster
        output not only thr RMS error) like I do with the kriging interpolator?
        if it is not possible tell me a method to do this,which software can I use?

        thank you for your availability



        --
        * 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
      Your message has been successfully submitted and would be delivered to recipients shortly.