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Re: GEOSTATS: Extrapolation - time series data

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  • soma
    Hi Pierre, It is coincidence. I am currently looking for sources (papers) discussing the spatial interpolation topic. If you do not mind, could you email
    Message 1 of 3 , Sep 29, 2000
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      Hi Pierre,

      It is coincidence. I am currently looking for sources (papers) discussing
      the spatial interpolation topic.
      If you do not mind, could you email me both papers you have just written.

      Regards,

      Soma Trenggana
      ----- Original Message -----
      From: "Pierre Goovaerts" <goovaert@...>
      To: "Ulrich Leopold" <leop6101@...>
      Cc: <ai-geostats@...>
      Sent: Friday, September 29, 2000 1:17 AM
      Subject: Re: GEOSTATS: Extrapolation - time series data


      > Hi Ulrich,
      >
      > The first-order decision is whether you want to
      > use estimation or simulation which are two
      > approaches with different objectives: getting
      > a smooth picture of the spatial distribution of values
      > or modeling the spatial uncertainty though the generation
      > of a series of simulated maps.
      >
      > For both techniques, there are different ways to incorporate
      > secondary information and you mentioned the most common
      > ones: simple kriging with varying local means,
      > kriging with an external drift and cokriging.
      > It's hard to tell which one to choose since
      > results will depend on factors such as:
      > semivariogram models (range, nugget effect) for variables
      > and residuals, magnitude of the correlation between
      > primary and secondary variables, sampling intensity.
      > A good way to proceed would be to try the different
      > techniques and compare cross-validation results.
      >
      > I would recommend reading the following papers
      > I wrote recently on the topic:
      >
      > Goovaerts, P. 2000.
      > Estimation or simulation of soil properties? An optimization problem
      > with conflicting criteria. Geoderma, N.3-4, p.165-186.
      >
      > Goovaerts, P. 2000.
      > Geostatistical approaches for incorporating elevation into
      > the spatial interpolation of rainfall. Journal of Hydrology,
      > 228: 113-129.
      >
      > I have reprints of both papers in pdf format that I could
      > e-mail you if requested.
      >
      > Regards,
      >
      > Pierre
      >
      <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
      <><>
      >
      > ________ ________
      > | \ / | 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
      >
      http://www-personal.engin.umich.edu/~goovaert/
      >
      >
      <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
      <><>
      >
      >
      > On Thu, 28 Sep 2000, Ulrich Leopold wrote:
      >
      > > Dear list,
      > >
      > > I am looking for an appropriate geostatistical method to
      > > EXTRAPOLATE wind speed data which are measured on a regular
      > > grid (every 10 Minutes, smooth variability over time).
      > >
      > > There are measurements for 10m and 30m above surface. The 10m
      > > time series is complete over the the whole sampling time whereas
      > > the 30m one is not. A LONG tail (right hand side) consists
      > > completely of missing values (no data).
      > >
      > > I would like to use the exhaustively sampled 10m measurements as a
      > > secondary variable for extrapolating the 30m missing values. But I
      > > am not sure which method of the following is the most appropriate
      > > one:
      > >
      > > 1) Ordinary co-located cokriging
      > > 2) Simple kriging with varying local means (prior regression between
      > > primary and secondary variable, residual variogram)
      > > 3) Kriging with an external drift
      > > 4) Or even simulation
      > >
      > > >From my experience I would start with Kriging with external drift or
      > > colocated kriging and try to increase the result by an appropriate
      > > bivariate simulation.
      > >
      > > Thanks so far
      > >
      > > Ulrich
      > > ______________________________________________
      > >
      > > Ulrich Leopold
      > >
      > > Faculty of Geography and Geo Sciences
      > > University of Trier
      > >
      > > Engelstrasse 104
      > > 54292 Trier
      > > Germany
      > >
      > > Phone: ++49-(0)651-140764
      > > E-mail: leop6101@...
      > > URL: http://homepages.go.com/~uleopold/index.htm
      > > --
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