[GRASSLIST:7270] Re: Large Images Manipulation

[Hamish]

> I'm looking for directions on how to manipulate, programmatically,
> very large GeoTIFF images.
> 
> My concern is about memory exhaustion and I'm looking for some
> technique (or library) capable of doing image manipulations without
> loading the entire image in memory.


Hi Eduardo,

How big is "very large"?

I loaded a 1.8gb GeoTIFF (no compression) into GRASS the other day with
r.in.gdal. No problems. (GRASS got the job because ERDAS choked on it)

GRASS does most raster processing with only one row of data in memory at 
a time so it handles huge images & fine resolutions quite nicely.
(noteable exception I know of: r.in|out.mat)

Large file support (LFS, ie >2gb) is in newer versions of GRASS, but 
is only lightly tested. "./configure --enable-largefile"


For more general GeoTIFF manipulations that don't really need a full 
GIS, you might do better to use the gdal tools directly: 
gdal_translate & gdalwarp from  http://www.gdal.org.



Hamish