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

2132RE: [ai-geostats] modelling trend and kriging type

Expand Messages
  • PCollier@xstrata.com.au
    Jul 6, 2005
    • 0 Attachment
      RE: [ai-geostats] modelling trend and kriging type

      Hi all

      I may know this already, but what are the symptoms of data with a trend?  What is the difference between a dataset with a trend and a non-stationary dataset?

      Cheers


      Perry Collier

      Senior Mine Geologist
      Ernest Henry Mine  
      Xstrata Copper Australia
      Ph (07) 4769 4527
      Fx (07) 4769 4555
      E-mail PCollier@...
      Web http://www.xstrata.com
       
      PO Box 527
      Cloncurry QLD 4824
      Australia
       
      "Light travels faster than sound. That is why some people appear bright
      until you hear them speak"




      -----Original Message-----
      From: Pierre Goovaerts [mailto:Goovaerts@...]
      Sent: Friday, 1 July 2005 12:54 AM
      To: Recep kantarci; ai-geostats@...
      Subject: RE: [ai-geostats] modelling trend and kriging type


      To add to the excellent comments by Edzer and Gregoire,
       
      1. Universal kriging = kriging with a trend. The second terminology has been proposed by Andre
      Journel who felt that the term "universal" was vague and misleadingly "ambitious".
       
      2. Kriging with an external drift (KED) is mathematically the same as universal kriging (UK). Secondary variables
      are simply replacing the spatial coordinates used in UK.
       
      3. Regression kriging denotes all the techniques where the trend is modeled outside the kriging algorithm.
      There are various methods that can be used to model that trend, ranging from linear regression
      to neural networks. Kriging is used to interpolate the residuals. In practice these techniques have more
      flexibility than universal kriging in term of modeling the trend: multiple variables either categorical or
      continuous can be incorporated  easily and many sofwtare are available for this trend modeling.
      The only limitation is that the trend is modeled globally (i.e. the regression coefficients are constant
      in space) while in KED the coefficients are reestimated within each search window.
       
      Cheers,
       
      Pierre
       

      Pierre Goovaerts

      Chief Scientist at Biomedware

      516 North State Street

      Ann Arbor, MI 48104

      Voice: (734) 913-1098
      Fax: (734) 913-2201

      http://home.comcast.net/~goovaerts/

              -----Original Message-----
              From: Recep kantarci [mailto:recep_kantarci_1978@...]
              Sent: Thu 6/30/2005 9:38 AM
              To: ai-geostats@...
              Cc:
              Subject: [ai-geostats] modelling trend and kriging type
             
             
              Dear ai-geostats members
              
              When the data used has a trend, it is needed to model trend and in this case there exists various types of kriging to apply (universal kriging, kriging with a trend, regression kriging etc).

              If this is the case, does one should use the same type of kriging or different depending on modeling the trend using coordinates of target variable or using other (namely, secondary or auxillary) variables such as elevation or topography ? That is , are there a dinstinction depending on the type of variables to model the trend while kriging?

              
              Best regards
              Recep

             
        _____ 

              Yahoo! kullaniyor musunuz?
              Istenmeyen postadan biktiniz mi? Istenmeyen postadan en iyi korunma Yahoo! Posta’da
              http://tr.mail.yahoo.com <http://tr.mail.yahoo.com/>

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

      The information contained in this e-mail is confidential and is

      intended only for the use of the addressee(s).

      If you receive this e-mail in error, any use, distribution or

      copying of this e-mail is not permitted. You are requested to

      forward unwanted e-mail and address any problems to the

      Xstrata Queensland Support Centre.

      Support Centre e-mail: supportcentre@...

      Support Centre phone: Australia 1800 500 646

      International +61 2 9034 3710

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

    • Show all 10 messages in this topic