[R] your suggestions in MRMs
Sarah Goslee
sarah.goslee at gmail.com
Wed Apr 8 20:23:27 CEST 2015
Kristi,
The row names are utterly arbitrary. Each row is a separate site, and
sitelocation is a location variable (both intended to conceal the
absolute location, which is confidential since it's on private
property). It is NOT the Euclidean distance, nor is a row representing
a pair of sites.
If you look at the full example, dist() is used to calculate the
Euclidean distance as part of the MRM code.
Sarah
On Wed, Apr 8, 2015 at 1:49 PM, Kristi Glover <kristi.glover at hotmail.com> wrote:
> Hi R Users,
> I was trying to perfom multiple regression on resemblance matrices (MRMs). This technique in avaiable in "ecodist" package and looked at the example data to know how I need to organize my data set. I think the data is distance matrix but I was wondering the rows name. For example, there are (these are the subset of the data of "graze")
> sitelocation forestpct
> 1.1.2001 12.187743 63.88
> 1.2.2001 12.186077 71.33
> 2.1.2001 12.406362 72.45
> 2.2.2001 12.416265 77.13
> 3.1.1998 8.409213 18.35
>
> if we look at the first row, 1.1.2001: sitelocation (column) is 12.187.. which is the euclidean distance between two points (XY cordinates). But I was confused at the row name where 1.1.2001 which is to me is site1 and site1 of 2001. Isn't it supposed to be "0" if both are the same site. I think I misunderstood it. Any one can help me about what it is?
>
> I put the example for your reference
>
> install.packages("ecodist")
> library(ecodist)
> data(graze)
> graze[1:5,1:2]
>
> Thanks for your help
>
> KG
>
--
Sarah Goslee
http://www.functionaldiversity.org
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