[gdal-dev] bigtiff support maybe not working

[Jukka Rahkonen]

Margherita Di Leo <diregola <at> gmail.com> writes:


> 
> now I'm trying with:CACHE="--config GDAL_CACHEMAX 8000 -wm 2000"gdalwarp
$CACHE -srcnodata -9999 -dstnodata -9999 -r bilinear -tr $RES $RES $LIST
mosaik_$RES.tif -co TILED=YES
> 
> It is taking long, of course, but somehow it is working and I don't get error,
so I have good expectations.. I'll keep you posted about the results 
> 
> 
> 
> Actually it is taking forever.. after one day it only processed a dozen of
tiles.. any hint to try to speed up the process? Otherwise I will need ages to
get my job done 

A few suggestions:

- GDAL_CACHEMAX and -wm may still be far too big.
- Try with -wo SKIP_NOSOURCE=YES which is documented in 
http://gdal.org/structGDALWarpOptions.html#a0ed77f9917bb96c7a9aabd73d4d06e08
- It might work faster by using a single .VRT virtual raster as input (make is
with gdalbuildvrt utility) instead of adding source files one by one with
gdalwarp as I suppose your command is doing now.

There was some discussion about warping speed some years ago. I do not remember
what was the end result because I finally used another software for the task I
had then and I have not played much with creating big warped images since then.
However, the thread is probably worth reading. You can jump in for example at 
http://www.mail-archive.com/gdal-dev@lists.osgeo.org/msg03986.html

If you have really much imagery it may be faster to split the huge job into
smaller ones and create rectangular warped tiles into the target projection in
first phase and combine them in a second phase by combining them with
gdalbuildvrt and finally writing out to final BigTIFF with gdal_translate. Then
you can also use more computers for warping. 

-Jukka Rahkonen-