[GRASS-user] map algebra during r.in.gdal?

Hamish hamish_b at yahoo.com
Fri Aug 8 02:13:58 EDT 2008

Milton Cezar Ribeiro wrote:
> I would like to know if it is possible I make an map algebra
> when importing a .IMG file. As I am working with native wingrass,
> and the LFS (Large File System), almost to where I know, don´t
> suport my large files (12GB),

I don't know if the WinGRASS binaries were built with LFS support turned
on or not. Also memory requirements of r.in.gdal, most raster modules are very good with large maps, but a few are not.

> I would like to divide my 32Bits
> image by 200, and generate and raster map on 16bits.
> I know that if I divide my original IMG map by 200 on ERDAS
> and import it on GRASS the size of resulting file works
> find on my current system.

perhaps use gdal_translate to split it up into a series of smaller tiles, then import each individually-

The general way to make a 1280x1024 tile is like:
 gdal_translate -srcwin $XOFFSET $YOFFSET 1280 1024 source.img out.tif

I have a script here which uses that, maybe could be adapted:



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