Ozy,
Did you try with gdal_translate -of NITF src.tif output.tif -co
BLOCKSIZE=128 ? Does it give similar results ?
I'm a bit surprised that you even managed to read a 40Kx100K large NITF
file organized as scanlines. There was a limit until very recently that
prevented to read blocks whose one dimension was bigger than 9999. This
was fixed recently in trunk ( see ticket
http://trac.osgeo.org/gdal/ticket/3263 ) and branches/1.6, but it has
not yet been released to an officially released version. So which GDAL
version are you using ?
Does the output of gdalinfo on your scanline oriented input NITF gives
something like :
Band 1 Block=40000x1 Type=Byte, ColorInterp=Gray
Is your input NITF compressed or uncompressed ?
Anyway, with latest trunk, I've simulated creating a similarly large
NITF image with the following python snippet :
import gdal
ds = gdal.GetDriverByName('NITF').Create('scanline.ntf', 40000, 100000)
ds = None
and then creating the tiled NITF :
gdal_translate -of NITF scanline.ntf tiled.ntf -co BLOCKSIZE=128
The memory consumption is very reasonnable (less than 50 MB : the
default block cache size of 40 MB + temporary buffers ), so I'm not
clear why you would have a problem of increasing memory use.
ozy sjahputera a écrit :
I was trying to make a copy of a very large NITF image (about 40Kx100K
pixels) using GDALDriver::CreateCopy(). The new file was set to have
different block-size (input was a scanline image, output is to have a
128x128 blocksize). The program keeps getting killed by the system
(Linux). I monitor the memory use of the program as it was executing
CreateCopy and the memory use was steadily increasing as the progress
indicator from CreateCopy was moving forward.
Why does CreateCopy() use so much memory? I have not perused the
source code of CreateCopy() yet, but I am guessing it employs
RasterIO() to perform the read/write?
I was trying different sizes for GDAL cache from 64MB, 256MB, 512MB,
1GB, and 2GB. The program got killed in all these cache sizes. In
fact, my Linux box became unresponsive when I set GDALSetCacheMax() to
64MB.
Thank you.
Ozy
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