[gdal-dev] Re: gdalwarp large imagery faster?

[Hermann Peifer]

On 24/06/2010 16:40, GeoSpatial - Kevin wrote:
> Hi all,
>
> I am trying to re-project a very large imagery (size 40,000 by 40,000
> pixels, resolution ~120m) located at high latitudes (60N) to a standard
> wgs84. By searching some previous posts, I come up with the following
> command:
>
> gdalwarp  -of EHdr -t_srs EPSG:4326 -tr 0.001111 0.001111 --config
> GDAL_CACHEMAX 200 -wm 200 -wo SKIP_NOSOURCE=YES -r bilinear -multi
> input_ice.tif output_ice.tif
>
> it is working now but the speed is very slow - likely this will take 12
> hours... Any way to speed up or am I wrong selecting those parameters?
> Thanks.
>

- multi doesn't work for me:
CPLCreateThread: Fails to dummy implementation
ERROR 1: CPLCreateThread() failed in ChunkAndWarpMulti()

However, without the -multi switch, my input data (100m raster, 
48500x41500, Type=Int16) is warped in 34 minutes or so, see here:

time gdalwarp --debug on -of EHdr -t_srs EPSG:4326 -tr 0.001111 0.001111 
--config GDAL_CACHEMAX 200 -wm 200 -wo SKIP_NOSOURCE=YES -r bilinear 
map2c_100.tif output.tif

real    34m13.134s
user    5m24.524s
sys     0m9.973s

If I raise the values for GDAL_CACHEMAX and -wm, it takes about 15 
minutes. I am using GDAL 1.8dev, on a 64-bit Linux machine.

Hermann