[R-sig-Geo] Error with disaggregate

[Robert J. Hijmans]

Ned,

I see nothing wrong with your code. Works for me on Win7.  Perhaps
because of a fix in the chunk size (blockSize) computation in the
development version.
Can you check if it works with that version?

 install.packages("raster", repos="http://R-Forge.R-project.org")


I do not understand the error message though, as you should be writing
fewer bytes then 2^31
> 2^31 / (8*ncell(c))
[1] 4.532697

This may go away if you add a filename, and perhaps a datatype (FLT4S)  argument

c <- disaggregate(b, fact=32, filename='dis.tif', datatype='FLT4S')

Or if you set
rasterOptions(chunksize= ) temporarily to something lower.

I note that I should add a "block_fun" method to do this in one step

Robert

On Tue, Feb 18, 2014 at 9:47 AM, Ned Horning <horning at amnh.org> wrote:
> Hi -
>
> I am trying calculate the sum of blocks of Landsat pixels (30m resolution)
> that fit within MODIS pixels 960m resolution) and store that values at the
> Landsat cell size. To accomplish that I am running aggregate with the "sum"
> function on a Landsat band and then I run disaggregate on the result to get
> the resolution back to the Landsat pixel size. When I do this the
> disaggregate function gives me the following error:
> --
> Error in writeBin(v, x at file@con, size = x at file@dsize) :   only 2^31-1 bytes
> can be written in a single writeBin() call
> --
>
> I can recreate the error with this script:
> --
> a <- raster(nrows=7776, ncols=7616, xmn=718335, xmx=946815, ymn=-757485,
> ymx=-524205, crs="+proj=utm +zone=35 +datum=WGS84 +units=m +no_defs
> +ellps=WGS84 +towgs84=0,0,0")
> a[] <- 1
> b <- aggregate(a, fact=32, fun=sum)
> c <- disaggregate(b, fact=32)
> --
>
> I am running R 3.0.2 on Ubuntu 12.04 with version 2.2-12 of the raster
> package.
>
> Please let me know if you see any problems with my code.
>
> Thanks.
>
> Ned
>
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