[R-sig-Geo] Issue with as.polygonal (gpclib disabled?)

[Rolf Turner]

Try setting:

	spatstat.options(gpclib=TRUE)

You would have found out about this if you'd done

	licence.polygons()

as the start-up message from spatstat suggests.

	cheers,

		Rolf Turner

P. S.  The help on spatstat.options() says that gpclib defaults
to TRUE.  This is an error.  It now defaults to FALSE.  We will
fix this glitch in the help in the next release.

		R. T.

On 29/01/2011, at 7:05 AM, José M. Blanco Moreno wrote:

> Dear R users,
> I have been trying to convert a mask owin object (generated by  
> dilation)
> to a polygonal owin, but I am facing the following error message,  
> and I
> have not been able to find the solution, neither among the
> documentation, nor in the mailing lists. Any hint? I know that some
> packages (one package, perhaps) have changed recently (months ago)  
> their
> default behaviour with regards to gpclib, and I wonder if spatstats is
> one of these.
> Thank you in advance,
> José M.
>
> ##############################
>> library(spatstat); library(gpclib)
>
>> pins <- cbind(x=rnorm(60),y=rnorm(60))
>
>> pins <- as.data.frame(pins)
>
>> pins.owin <- owin(poly=pins[rev(chull(pins)),])
>
>> pins.dil <- dilation(pins.owin,r=0.25)
>
>> pins.dil <- simplify.owin(dilation(pins.owin,r=0.25))
> # Warning message:
> # In as.polygonal(W) :
> #   Can't convert mask to polygon: gpclib is disabled/unavailable
>
>> perimeter(pins.dil)
> # Error in as.psp.owin(p) : x is a mask
> # In addition: Warning messages:
> # 1: In as.polygonal(w) :
> #   Can't convert mask to polygon: gpclib is disabled/unavailable
> # 2: In as.polygonal(W) :
> #  Can't convert mask to polygon: gpclib is disabled/unavailable
>
> ##############################
> ## However I can execute the following example from gpclib
>> holepoly <- read.polyfile(system.file("poly-ex/hole-poly.txt",  
>> package =
> + "gpclib"), nohole = FALSE)
>
>> area.poly(holepoly)
>
>> sessionInfo()
> R version 2.11.0 (2010-04-22)
> i386-pc-mingw32
>
> locale:
> [1] LC_COLLATE=Spanish_Spain.1252  LC_CTYPE=Spanish_Spain.1252
> [3] LC_MONETARY=Spanish_Spain.1252 LC_NUMERIC=C
> [5] LC_TIME=Spanish_Spain.1252
>
> attached base packages:
> [1] stats     graphics  grDevices utils     datasets  methods   base
>
> other attached packages:
> [1] gpclib_1.5-1    spatstat_1.21-0 deldir_0.0-12   mgcv_1.7-1
>
> loaded via a namespace (and not attached):
> [1] grid_2.11.0        lattice_0.19-13    Matrix_0.999375-44  
> nlme_3.1-97
> [5] tools_2.11.0
>
> -- 
> ---------------------------------------
> José M. Blanco-Moreno
>
> Dept. de Biologia Vegetal (Botànica)
> Facultat de Biologia
> Universitat de Barcelona
> Av. Diagonal 645
> 08028 Barcelona
> SPAIN
> ---------------------------------------
>
> phone: (+34) 934 039 863
> fax: (+34) 934 112 842
>
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