AI-GEOSTATS: Summary: Log-normal back transform in Webster & Oliver]
- Hello again,
Murray's reply to my question says it all. Thanks again a lot to Isobel Clark
(special thanks for the nice explanation on the behaviour of the Lagrange
parameter !), Gerard Heuvelink and Murray Lark.
------ Original Message ------
Received: Mon, 28 Jul 2003 06:22:12 PM CEST
From: "murray lark (SRI)" <murray.lark@...>
To: 'Gregoire Dubois' <gregoire.dubois@...>
Subject: RE: AI-GEOSTATS: Log-normal back transform in Webster & Oliver
Just to follow up my previous email, I have had a word with Dick Webster who
confirms that the missing Lagrange multiplier in Equation 8.38 was a printing
error, he thanks you for pointing it out. Also note that the Lagrange
multiplier should have an argument, bold x_0, since it is specific to the
kriging target site.
From: Gregoire Dubois [mailto:gregoire.dubois@...]
Sent: 28 July 2003 10:39
Subject: AI-GEOSTATS: Log-normal back transform in Webster & Oliver
In the book "Geostatistics for Environmental Scientists"
By Richard Webster & Margaret A. Oliver, Wiley (2000), one will find in page
180 a brief discussion on the back-transformation of the kriging estimates.
In ordinary kriging, when the natural logarithm (ln) is used, the
back-transformation will involve the Lagrange parameter (see equation 8.36).
No problem so far.
But... the authors write in equation 8.38 that if one is using common
logarithms (log10) instead, the unbiased back-transformation of the ordinary
kriging estimates does not involve the Lagrange multiplier anymore.
Is this correct ? In the affirmative, can someone point me to a paper
discussing "natural" log normal kriging versus "common" log normal kriging ?
Thanks again for any help.
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