auto-correlation of nominal variables

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auto-correlation of nominal variables

Emanuele Barca
Dear friends,

I received a  dataset of point data, organized in the following way:

a couple of coordinates and a column of "crop classes codes", three
columns.

I would like to compute something similar to the Moran index for each
crop class code.

How can I carry out such task in R?

thanks in advance

emanuele

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Re: auto-correlation of nominal variables

Roger Bivand
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On Sun, 16 Jun 2019, Emanuele Barca wrote:

> Dear friends,
>
> I received a  dataset of point data, organized in the following way:
>
> a couple of coordinates and a column of "crop classes codes", three columns.
>
> I would like to compute something similar to the Moran index for each crop
> class code.
>
> How can I carry out such task in R?

spdep::joincount.multi() and spdep::joincount.test().

and read the references on the help pages. See eg.

https://keen-swartz-3146c4.netlify.com/area-data-and-spatial-autcorrelation.html#measures-of-spatial-autocorrelation

Roger

>
> thanks in advance
>
> emanuele
>
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> R-sig-Geo mailing list
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>

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Department of Economics, Norwegian School of Economics,
Helleveien 30, N-5045 Bergen, Norway.
voice: +47 55 95 93 55; e-mail: [hidden email]
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Re: auto-correlation of nominal variables

Rich Shepard
In reply to this post by Emanuele Barca
On Sun, 16 Jun 2019, Emanuele Barca wrote:

> I received a  dataset of point data, organized in the following way: a
> couple of coordinates and a column of "crop classes codes", three columns.

> I would like to compute something similar to the Moran index for each crop
> class code.

Emanuele,

What is your interest in these data? Are you interested in the pattern of
crop classes (such as in epidemiology or designing a timber sale) or
something else?

If it is the pattern that is of interest I suggest you first test for
complete spatial randomness. Look at some of the references and R packages
for spatial point processes. The distribution of crop classes could be
random, regular, or clumped/clustered.

Peter Diggle's book, "Statistical Analysis of Spatial Point Patterns," and
"Spatial Point Patterns" by Adrian Baddeley, Ege Rubak, and Rolf Turner
would be excellent places to start.

Hope this helps,

Rich

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