Jukka wrote
From: Hermann Peifer <peifer <at> gmx.eu>

A promising approach seemed to be to warp/resample the ASTER files one by one 
and create 1500 separate tiles
in LAEA projection, as an intermediate step. Then I created a vrt file with 
gdalbuildvrt and
gdal_translated it into tiff format. The result did however look odd, as the 
elevation data in most tiles
was clipped by NODATA areas of their neighbouring tiles :-(

Hi,
Did you try to use gdalwarp also for the second step with -srcnodata value 
[value...]?  I believe you did set some NODATA value in step 1 for the 
intermediate images.

-Jukka Rahkonen-

I did. However, the main problem with gdalwarp is its performance. So my 
options seem to be:

1.
gdalwarping 1500 ASTER tiles in 1 run into a 4GB 100m raster output.tif
= 5-10 days processing (my best estimate)

2.
gdalwarping 1500 ASTER tiles 1-by-1 as an intermediate step, then
gdal_merge or gdal_translate to mosaic warped tiles into output.tif
= smaller or larger NODATA areas in output.tif, along tile borders

Today I resorted to Plan B, which is option A with a 250m raster output.tif. 
This is not exactly what I want to have, but seems to be doable in ~1 day.

Hermann

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