Hi
I was investigating my data and it is possible to identifie areas of
zeros on the outside limits of the distribution, so it can be possible
to model the spatial behaviour in two steps.
My guess is that I can simple reduce the kriging area to leave the zero
area out.
My doubt is how to
Hi
I'm analysing fisheries data (number of fish caught per hour) and I have
some 0 values. When I log-trans I have to translate the values by hading
some value.
My question is which value is the best ? is there any works about this ?
I usually had 1 so that I get values between 0 and infinite
Ernesto
There are several ways of tackling skewed data with
zeroes and I am sure you will get emails from
proponents of this or that other contributor.
Ways which I have found useful:
(1) try a lognormal probability plot and see whether
you have a straight line or if it drops off the line
at
problem domain. Thereafter krige within a limited search
neighborhood or try an indicator approach at various
thresholds.
Syed
Original message
Date: 02 Oct 2002 12:24:57 +0100
From: Ernesto Jardim [EMAIL PROTECTED]
Subject: AI-GEOSTATS: Log transformation and zeros
To: Mailing List AI
Hi
The data are not discrete. We collect number per hour, so it's a yield !
Thanks
EJ
On Wed, 2002-10-02 at 15:27, Nicholas Lewin-Koh wrote:
Hi,
If the data are counts, ie integer number of fish and not tons, you
might want to try a discrete model such as a negative binomial or
Poisson. I
Hi
I'm analysing fisheries data (number of fish caught per hour) and I have
some 0 values. When I log-trans I have to translate the values by hading
some value.
I guess you mean you have to do something arbitrary about the zeros before
the log transform. The delta distribution is a
