[GRASSLIST:7276] Re: Large Images Manipulation

[Eduardo Bezerra]

Hi Hamish,

Thanks for the reply.

I'm new to the field of image manipulation and GIS, so I'm a little
lost in what direction I should take. I only found about GRASS
searching the subject of image manipulation on the Internet.

What I really need is a library that implements the memory allocation
and image manipuation routines for GeoTIFF images. And, since the
images are big (from 1Gb to 2Gb) it must not load the entire image
in memory. This library will be the basis of a custon GeoTIFF viewer
application.

Do you think I can find something like this in http://www.gdal.org ?

My best regards,
Eduardo


On 6/22/05, Hamish <hamish_nospam at yahoo.com> wrote:
> > 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
>