[R-sig-Geo] Package sp: image() and breaks= for SpatialGridDataframe

[Edzer Pebesma]

On 02/03/2011 10:10 AM, Ghislain Vieilledent wrote:
> Dear list,
> 
> I encountered a problem using function image() and argument breaks on a
> SpatialGridDataFrame object (package sp version 0.9-76, R version 2.12.1
> (2010-12-16) on Ubuntu 10.04).
> 
> I had to use function as.image.SpatialGridDataFrame before to obtain the
> correct colored graphic:
> 
> # Doesn't work:
> image(SDAzD.As.A2a.2080,breaks=c(seq(0,0.5,0.1),1),col=c(grey(seq(0.9,0.5,-0.1)),"dark green"))
> 
> # Works:
> xyz <- as.image.SpatialGridDataFrame(SDAzD.As.A2a.2080)
> image(xyz,breaks=c(seq(0,0.5,0.1),1),col=c(grey(seq(0.9,0.5,-0.1)),"dark
> green"))
> 
> Is this a normal behavior ?

Yes, as the image method is called with different objects, try

class(xyz)
class(SDAzD.As.A2a.2080)

to find out. You get the respective help pages by

?image
?image.SpatialGridDataFrame

> 
> Best regards,
> 
> Ghislain
> 

-- 
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