[GRASSLIST:7277] Re: Large Images Manipulation

[Jonathan Greenberg]

Also, if you are using MacOS X.3 and earlier, you can't access > 2gb files.
By any chance has anyone tried Tiger and large files yet?  In theory Tiger
should have started supporting 64-bit file access...

--j


On 6/21/05 10:40 PM, "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
> 


-- 
Jonathan A. Greenberg, PhD
NRC Research Associate
NASA Ames Research Center
MS 242-4
Moffett Field, CA 94035-1000
650-604-5896
AIM: jgrn307
MSN: jgrn307 at hotmail.com