[gdal-dev] gdalwarp on large files

[Even Rouault]

Laura,

From the error message, I guess you are running gdalwarp on a remote server 
through a ssh connexion. There's probably a timeout that occurs since your 
operation takes hours. You should check the ssh options of the client/server 
for that.

In your use case, if you just want to create a mosaic of SRTM files and not 
really warp them, you'd better use gdalbuildvrt to create quickly a VRT file 
(XML-based) and then translate it to geotiff. This should run much faster 
than gdalwarp. But the 432001P x 40801L output size will remain. As it is 
huge, it will also likely take some time !

gdalbuildvrt mosaic.vrt *hgt
gdal_translate mosaic.vrt mosaic.tif

If you only use the mosaic with GDAL enabled tools, you can skip the 
gdal_translate step. That will save space (17.6 GB!) and time (a few seconds 
v.s. several hours).

Best regards,
Even

Le Monday 01 June 2009 19:58:44 Laura Toma, vous avez écrit :
> Hi,
>
> I am trying to create a large DEM from SRTM3 data.  I have a folder
> 'australia' which includes 1060 .hgt tiles downloaded from
> 'rome0srp01u.ecs.nasa.gov/', and I am trying to create a tiff for all
> the tiles in this folder.
>
> I have tried to run 'gdalwarp'  several times and every time the
> server gets reset (see below) after  processing the first .hgt file.
> The tiles are not that large (i think i3600x3600), but processing the
> first tile takes hours.
>
> Has anybody tried anything similar? Am I doing something wrong?  Any
> advise would be greatly appreciated.
>
> thanks,
> Laura
>
>  > gdalwarp *hgt srtm_mosaik_australasia.tiff
>
> Creating output file that is 432001P x 40801L.
> Processing input file S11E119.hgt.
> Using internal nodata values (eg. -32768) for image S11E119.hgt.
> 0...10...20...30...40...50...60..Read from remote host cod: Connection
> reset by peer
>
> _______________________________________________
> gdal-dev mailing list
> gdal-dev at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/gdal-dev