[R-sig-Geo] unionSpatialPolygons

[Paul Hiemstra]

Dear Mihai,

You need to install the gpclib package (available from CRAN). The error 
occurs because it tries to use a function from that package while it is 
not installed.

cheers,
Paul

Mihai Nica wrote:
> XP, R and Tinn-R up to date.
>
> Greetings:
> I've been away from the list for quite some time, and (as expected) some things change. My understanding is that maptools contains "unionSpatialPolygons". However, the following code (which previously worked):
> #______________________________________________________________
> library(maptools)
> msa_cmsa <- readShapePoly("1999_MSA_CMSA") # puts shapefile in SpatialPolygonsDataFrame
> summary(msa_cmsa)
> msa_cmsaaggregated=unionSpatialPolygons(msa_cmsa, msa_cmsa$MSACMSA)
> #_______________________________________________________________
> leads to:
>
>   
>> msa_cmsaaggregated=unionSpatialPolygons(msa_cmsa, msa_cmsa$MSACMSA)
>>     
> Loading required package: gpclib
> Error in as(pli[[1]], "gpc.poly") : 
>   no method or default for coercing "matrix" to "gpc.poly"
> In addition: Warning message:
> In library(package, lib.loc = lib.loc, character.only = TRUE, logical.return = TRUE,  :
>   there is no package called 'gpclib'
>
> May I ask for a hint?
>
> thanks,
>
> mihai
>
>
>
>
>
>       ____________________________________________________________________________________
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>
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-- 
Drs. Paul Hiemstra
Department of Physical Geography
Faculty of Geosciences
University of Utrecht
Heidelberglaan 2
P.O. Box 80.115
3508 TC Utrecht
Phone: 	+31302535773
Fax:	+31302531145
http://intamap.geo.uu.nl/~paul