Hi
I have a set of two dimensional data( measured on a grid). Initial
analysis strongly suggests that there is directional anisotropy, so I've
been trying to deal with this.
One way I've found is to fit the variogram model by maximum likelihood
(or REML) using geoR. geoR seems to account for
Hi!
There is something about negative weights in "geostatistics for natural
Resources Evaluation" of Pierre Goovaerts. Also in Srivastava's
"Applied geostatistics" you can find something of useful.
Sebastiano
At 05:29 PM 9/4/2003 +0200, [EMAIL PROTECTED] wrote:
Hi Mailinglist!!!
I have go
Hi Laure,
One of the main culprits for negative cokriging weights
is the ordinary cokriging constraint that the sum of the
secondary weights must be zero. I found that the frequency
and magnitude of negative cokriging weights greatly decreased
when using a single constraint that primary and second
Laure
You will probably get lots of replies on this and
plenty of references, so I will stick to what I know.
Possible reasons for large negative weights:
(a) samples are too close together with low nugget
effects on the semi-variogram models. This leads to
precision problems in solving the equat
Ursula
> 5.5 x 20 metres
> Choosing a 5 metres lag, the variance
> values are too high in the first 3 -4 lags.
This is possibly because you have some competition
effect between orchids.
For a square grid, we usually recommend an interval
20% of the grid spacing, so you don't get diagonals
lumped
Laure FONTAINE
Services des Réserves
COGEMA BUM/DT
tél: 33 1 39 26 32 05
Fax: 33 1 39 26 27 31
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Hi Mailinglist!!!
I have got some problems with negative weight in my cokriging, they induce
negative grade. Have you got some advice or publication to help me.I hope
you can help me with some of your answers.
Thank
Laure
Laure FONTAINE
Services des Réserves
COGEMA BUM/DT
tél: 33 1 39 26 32 0
Hi there,
can anybody here tell me how to choose the correct (appropriate) lag
distance for a regular sampling grid for orchids of 5.5 x 20 metres
(Counting data at a certain quadrate) ? I have problems in variogrphy,
because lag distances of 5 metres seem to be problematic because of the
regu
Hi Gregoir, Hi Mailinglist !
thank you very much for the information !
I am analysing plants in grassland and I have the problem, that many
researchers here use linear triangulation in r e g u l a r (20 x 20 metres)
sampling grids to estimate the population for mapping. Natural Neighbors
seems
