[R-sig-Geo] how to pass panel index in spplot

[Weidong Gu]

Thanks Edzer for advising the option. But I could not figure out how to draw spatial polygons like state map with xyplot.

Weidong

> -----Original Message-----
> From: Edzer Pebesma [mailto:edzer.pebesma at uni-muenster.de]
> Sent: Wednesday, April 07, 2010 3:09 PM
> To: Weidong Gu
> Cc: 'r-sig-geo at stat.math.ethz.ch'
> Subject: Re: [R-sig-Geo] how to pass panel index in spplot
> 
> Dear Weidong,
> 
> for multi-group panel functions, the way to retrieve subscripts in
> custom panel functions is
> 
> panel = function(x,y,subscripts, ...) {
>  ... # do sth with subscripts here
> }
> 
> see also
> 
> library(lattice)
> ?panel.superpose
> 
> I hope this helped,
> 
> Weidong Gu wrote:
> > Hi,
> >
> > I have a question about spplot: can it transfer somehow panel index,
> such as subscripts in xyplot to panels.
> >
> > The question arose when I needed to plot numbers of disease incidents
> on state map. The reproducible code is below. I thought panel=function
> () might be the solution but I couldn't get panel index in individual
> panels.
> >
> > library(maps)
> > library(maptools)
> > state=map('state',plot=F,fill=T)
> > IDs=sapply(strsplit(state$names,':'), function(x) x[1])
> > crs=CRS('+proj=longlat +ellps=WGS84')
> > sp.st=map2SpatialPolygons(state, IDs, proj4string=crs)
> >
> > state.inc=data.frame(State=sapply(slot(sp.st,'polygons'),function(x)
> slot(x,'ID')))
> > state.inc$D1=rpois(length(state.inc$State),100)
> > state.inc$D2=rpois(length(state.inc$State),150)
> > row.names(state.inc)=state.inc$State
> > inc.spdf=SpatialPolygonsDataFrame(sp.st,state.inc)
> >
> > spplot(inc.spdf, zcol=2:3,
> >     panel = function(...) {
> >         sp.polygons(inc.spdf)
> >         sp.text(coordinates(inc.spdf),zcol)
> >     }
> >     )
> >
> > I would appreciate you help and advice.
> >
> > Weidong Gu
> > University of Alabama, Birmingham
> > 220A Bevill Biomedical Research Bldg
> > 845 19th Street S., Birmingham, Alabama 35294
> >
> > _______________________________________________
> > R-sig-Geo mailing list
> > R-sig-Geo at stat.math.ethz.ch
> > https://stat.ethz.ch/mailman/listinfo/r-sig-geo
> 
> --
> Edzer Pebesma
> Institute for Geoinformatics (ifgi), University of Münster
> Weseler Straße 253, 48151 Münster, Germany. Phone: +49 251
> 8333081, Fax: +49 251 8339763  http://ifgi.uni-muenster.de
> http://www.52north.org/geostatistics      e.pebesma at wwu.de