[R-sig-Geo] plotting Polygon (sp)

[Sebastian P. Luque]

Hi,

Using the example from the vignette "sp" (section 7.1):

---<--------------------cut here---------------start------------------->---
R> sr1
An object of class "Polygon"
Slot "labpt":
[1] 2.697 3.545

Slot "area":
[1] 5.5

Slot "hole":
[1] TRUE

Slot "ringDir":
[1] -1

Slot "coords":
     [,1] [,2]
[1,]    2    2
[2,]    4    3
[3,]    4    5
[4,]    1    4
[5,]    2    2

R> plot(sr1)
Error in as.double(y) : 
  cannot coerce type 'S4' to vector of type 'double'
R> showMethods("plot")
Function: plot (package graphics)
x="ANY", y="ANY"
x="Polygon", y="missing"
    (inherited from: x="ANY", y="ANY")
x="SpatialLines", y="missing"
x="Spatial", y="missing"
x="SpatialPoints", y="missing"
x="SpatialPolygons", y="missing"

R> sessionInfo()
R version 2.11.1 (2010-05-31) 
x86_64-pc-linux-gnu 

locale:
 [1] LC_CTYPE=en_CA.UTF-8       LC_NUMERIC=C               LC_TIME=en_CA.UTF-8       
 [4] LC_COLLATE=en_CA.UTF-8     LC_MONETARY=C              LC_MESSAGES=en_CA.UTF-8   
 [7] LC_PAPER=en_CA.UTF-8       LC_NAME=C                  LC_ADDRESS=C              
[10] LC_TELEPHONE=C             LC_MEASUREMENT=en_CA.UTF-8 LC_IDENTIFICATION=C       

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] rgdal_0.6-27    maptools_0.7-34 foreign_0.8-40  mapdata_2.1-2   maps_2.1-3     
[6] sp_0.9-64       slmisc_0.7.6    lattice_0.18-8 

loaded via a namespace (and not attached):
[1] grid_2.11.1  tools_2.11.1
---<--------------------cut here---------------end--------------------->---

Why is plot() failing with that error?


Cheers,

-- 
Seb