[R-sig-Geo] Using 'overlay' with multi- and single-layers objects

[Robert J. Hijmans]

Hi Kevin,

That's a bug, thanks for reporting it. Fixed in version 1.7-1

A work around for the simple example you provide would be:

x <- stack_r + r

or (not really advisable but it should work while version 1.7-1 is not
yet on CRAN)

x <- raster:::.overlayList( list(stack_r,r), fun=sum)

Robert




On Tue, Nov 23, 2010 at 3:25 AM, Kevin Ummel <kevinummel at gmail.com> wrote:
> Can someone tell me why the following generates an error? The 'overlay' description in the 'raster' package suggests the single-layer object should recycle as needed...
>
> Thanks!
> Kevin
>
>> r <- raster(ncol=10, nrow=10)
>> r <- init(r, fun=runif)
>> stack_r=stack(r,r)
>
>> overlay(stack_r,r,fun=sum)
> Error in function (classes, fdef, mtable)  :
>  unable to find an inherited method for function "overlay", for signature "RasterStack", "RasterLayer"
>
> Seems to me that the command above should be able to replicate:
>
>> stack_r+r
> class       : RasterBrick
> filename    :
> nlayers     : 2
> nrow        : 10
> ncol        : 10
> ncell       : 100
> projection  : +proj=longlat +datum=WGS84 +ellps=WGS84 +towgs84=0,0,0
> min value   : 0.011 0.011
> max value   : 2 2
> extent      : -180, 180, -90, 90  (xmin, xmax, ymin, ymax)
> resolution  : 36, 18  (x, y)
>
> I need single-layer objects used as arguments within 'overlay' to recycle for more complex functions that include raster stacks...
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