[R] your suggestions in MRMs

Kristi Glover kristi.glover at hotmail.com
Wed Apr 8 21:01:37 CEST 2015

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Hi Sarah,

Thanks for the reply. I again looked at the example, but I did not find the way to
calculate the location variable. All example in the document
("ecodist") has the Euclidean distance. did not find the example to
conceal the absolute location. There are some example:

page 21 and 22 : iris.md <- distance(iris[,1:4], "mahal"): it is
calculated distance matrix using four variables (I understood this one)

page 26: space.d <- distance(space, "eucl"), here space is XY coordinate,
so on

I am just wondering how I can conceal my absolute location (XY) and make my
data compatible to your data set so that I can use your functions. I am sorry for bothering you, Sarah.

example of my data set: column names (site,
XY coordinates, temp, years)

site1, 25.01;34.78 (XY cordicnate),
35degree celcius; year2001

site1, 25.01;34.78 (XY cordicnate), 33degree celcius;
year2002

site2, 25.05; 35.56 (XY coordinate); 37degree
celcius; year2001

site2, 25.05; 35.56 (XY coordinate);
32degree celcius; year2002

Thanks

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> Date: Wed, 8 Apr 2015 14:23:27 -0400
> Subject: Re: [R] your suggestions in MRMs
> From: sarah.goslee at gmail.com
> To: kristi.glover at hotmail.com
> CC: r-help at r-project.org
>
> 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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