[R-sig-Geo] polygon neighbor matrix

[Roger Bivand]

On Mon, 31 Aug 2015, Paul Lantos wrote:

> Hi,
>
> I'm trying to use the cluster analysis program Flexscan, which I gather 
> is similar to Satscan but it computes irregular clusters. This program 
> requires a polygon adjacency matrix (termed a 'matrix definition file'). 
> The example they provide has a row for every polygon, and for each row 
> every neighboring polygon is listed in successive columns. So for 
> instance if row 1 / polygon 1 has 3 neighbors there will be three 
> polygons listed in columns 2-4.
>
> I have tried some techniques like the spatial weights matrix tools in 
> ArcGIS and in Spatstat, but I cannot get the output in this kind of 
> format. Was wondering if there is some obvious way to do this in R.
>
> The documentation for Flexscan is here:
>
> https://sites.google.com/site/flexscansoftware/download_e/FleXScan%20User%20Guide_e31.pdf?attredirects=0&d=1

Something like:

library(spdep)
example(nc.sids)
out <- sapply(seq(along=ncCR85_nb), function(i) paste(attr(ncCR85_nb,
   "region.id")[i], paste(attr(ncCR85_nb, "region.id")[ncCR85_nb[[i]]],
   collapse=" ")))
writeLines(out, tf)
file.show(tf)

See also:

vignette("nb")

Roger

>
> Thanks for any help,
> Paul
>
> _______________________________________
> Paul M. Lantos, MD, FIDSA, FAAP, FACP
> Departments of Internal Medicine and Pediatrics
>  Pediatric Infectious Diseases
>  Hospital Medicine Program
> Duke University School of Medicine
> _______________________________________
>
>
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-- 
Roger Bivand
Department of Economics, Norwegian School of Economics,
Helleveien 30, N-5045 Bergen, Norway.
voice: +47 55 95 93 55; fax +47 55 95 91 00
e-mail: Roger.Bivand at nhh.no