[R-sig-Geo] raster package

[Robert Hijmans]

Agus,

> Is there a way
> of assigning the tif file to an R raster object and then just use
> reclass() and R would
> read the file by pieces as needed? That's what I would like to...

That is exactly what is intended with reclass(). Something like this :

r <- raster('mytiffile.tif')
m <- matrix(0,1000,1, 1000, Inf, NA, ncol=2)
rc <- reclass(r, m, ...)

Robert

On Tue, May 19, 2009 at 1:36 AM, Agustin Lobo <alobolistas at gmail.com> wrote:
> I have to reclassify a large (> 8000x8000 pixels) geotif raster. I normally
> would do it through grass (or saga) but would like to try the raster
> package in R.
> The problem is that I'm a bit confused on how to do it. My understanding
> of the package
> is that it provides a way to operate in the rasters by pieces, not having
> to read the whole thing into memory. I've seen there's a function reclass()
> but how do I actually read the raster? If I use readAll() this is going
> to be as
> using readGDAL() directly, so this is not the way. Do I have to use
> a for() of readRows(), then reclass()? This seems a bit low-level. Is
> there a way
> of assigning the tif file to an R raster object and then just use
> reclass() and R would
> read the file by pieces as needed? That's what I would like to...
>
> Agus
>
>
>
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