Total inertia in package Vegan?

Wed, Nov 17, 2010 4:23 AM #

Dear all at the R-project help list.

I have run into a problem when it comes to getting values for "total inertia" and "R-squared" for my DCA using "decorana" in the package "vegan". I have tried the "goodness" function, but the reply indicates that it does not work with "decorana" class objects. In Canoco one gets the Total inertia in the output together with 4 eigenvalues. In decorana one gets the 4 eigenvalues, but not the Total inertia.

Is there a way for me to get the Total inertia without having to go over to Canoco?

Best regards,

Petter Hedberg


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7 days later

Gavin Simpson

Wed, Nov 24, 2010 4:49 AM #

On Wed, 2010-11-17 at 13:23 +0100, Hedberg Peter wrote:

OK, I might well be being incredibly stupid, but Total Inertia doesn't
change with CA/DCA. Just run cca() on your matrix and grab the inertia.
Whether you can compare the eigenvalues from decorana() and cca() I
can't quite remember. Jari should be able to tell you - drop us a line
on the Vegan R-Forge page:

https://r-forge.r-project.org/forum/forum.php?forum_id=194&group_id=68

I'll take this opportunity to question why you are using DCA at all?

G

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