Hi David,

I think it is possivel, but if you will deal with large images,
I hardly suggestion you handle this on GRASS,
and if you need play with R, you use spgrass6() package
to connect R on grass.

good luck

milton

On Wed, Sep 9, 2009 at 1:19 PM, David Mireles <dmireles@gmail.com> wrote:

> I'm new to rgdal and gdal--  I have a very large nitf image (too big
> to fit in memory) that I would like to extract subset areas of
> interest based on a center lat/long coordinate (and possibly an
> elevation). I would like to use the getRasterData function extract the
> AOI (which requires pixel x,y offsets). How can I get the row/column
> (x,y) for a specific lat/long coordinate in an spatial (latlon) image?
>  I believe in gdal there is a gdaltransform tool where you supply the
> image, specify -i (inverse) and -rpc and it will return the x,y point.
> Anyone know how I can do this in rgdal? (Will spTransform do this? Do
> I need make a .Call to some GDAL function?)
> Thanks in advance,
> dm
>
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