[R-sig-Geo] A global autocorrelation statistic for categorical data?

[Pedro Perez]

Thanks a lot!

Best!

Pedro

El mar, 16 feb 2021 a las 11:02, Roger Bivand (<Roger.Bivand using nhh.no>)
escribió:

> On Tue, 16 Feb 2021, Pedro Perez wrote:
>
> > Hello everybody!
> >
> > Sorry for the dumb question, I have very limited experience with regards
> to
> > spatial autocorrelation. I have a lot of spatial points for which I
> > measured both continuous and categorical variables. I need to calculate
> > *global* measures of spatial autocorrelation for both kinds of
> variables. I
> > know that this task is relatively easy for continuous ones, here an
> example
> > using the package elsa:
> >
> > rm(list = ls())
> > library(raster)
> > library(elsa)
> >
> > dta <- data.frame(Lon = (runif(60)*100),
> >                              Lat = (runif(60)*100),
> >                              Cat = sample(LETTERS[1:5], 60, replace = T),
> >                              Cont = (runif(60)*100))
> > coordinates(dta) <- ~Lon + Lat
> > # Moran's I global index:
> > moran(dta[,2], d1=0, d2=2000)
> > [1] -0.01694915 # The value varies given that seed was not set
> > # Geary's c global index:
> > geary(dta[,2], d1=0, d2=2000)
> > [1] 1
>
> set.seed(1)
> dta <- data.frame(Lon = (runif(60)*100),
>                                Lat = (runif(60)*100),
>                                Cat = sample(LETTERS[1:5], 60,
>                                             replace = TRUE),
>                                Cont = (runif(60)*100))
> coordinates(dta) <- ~Lon + Lat
> library(spdep)
> nb <- dnearneigh(dta, 0, 50) # 2000 was far too big, all neighbours of all
> moran.test(dta$Cont, nb2listw(nb, style="B"))$estimate[1]
> elsa::moran(dta[,2], d1=0, d2=50)
> geary.test(dta$Cont, nb2listw(nb, style="B"))$estimate[1]
> elsa::geary(dta[,2], d1=0, d2=50)
> joincount.multi(factor(dta$Cat), nb2listw(nb, style="B"))["Jtot",]
>
> Jtot summarises all the k-colour matches.
>
> Hope this clarifies,
>
> Roger
>
> >
> > That is, I need something like the moran or geary commands in the
> previous
> > example, but applicable to categorical covariates. I have been googleing
> > for a while, but I have not been able to find a solution. Any idea?
> >
> >
> > Thanks in advance!
> >
> >
> > Perep
> > ResponderReenviar
> >
> >       [[alternative HTML version deleted]]
> >
> > _______________________________________________
> > R-sig-Geo mailing list
> > R-sig-Geo using r-project.org
> > https://stat.ethz.ch/mailman/listinfo/r-sig-geo
> >
>
> --
> Roger Bivand
> Department of Economics, Norwegian School of Economics,
> Helleveien 30, N-5045 Bergen, Norway.
> voice: +47 55 95 93 55; e-mail: Roger.Bivand using nhh.no
> https://orcid.org/0000-0003-2392-6140
> https://scholar.google.no/citations?user=AWeghB0AAAAJ&hl=en
>

	[[alternative HTML version deleted]]