[GIS] Nonstandard GDAL and BIGTIFF: Is there a hidden flag / env variable

gdalgdal-mergegeotiff-tiff

I'm having some trouble with GDAL and BIGTIFF support. I work on a multi user cluster, and the defaults for GDAL are 1.9.2 there. I've built GDAL 2.1.3, libtiff, libgeotiff, and proj4, making sure to use BIGTIFF support. Everything works fine during the build, and the configure recognizes bigtiff during the GDAL build. All good.

However, when I attempt to use gdal_merge.py, I get the following errors thrown:

<GDALPATH>/bin/gdal_merge.py
Warning 6: Driver GTiff does not support BIGTIFF creation option
Warning 6: BigTIFF requested, but GDAL built without BigTIFF
enabled libtiff, request ignored

I've set my environment variables as:

export PATH=<GDALPATH>/bin:${PATH}
export LD_LIBRARY_PATH=<GDALPATH>/lib
export LD_RUN_PATH=<GDALPATH>/lib
export PYTHONPATH=<GDALPATH>/lib64/python2.6/site-packages

When I run gdal_merge.py –version, I get the correct gdal library, with the version as: 

GDAL 2.1.3, released 2017/20/01

But when I run the actual gdal_merge.py , I get the error listed above. Everything built / installed correctly, but for some reason, despite configuring and building with it, the gdal_merge call won't use BIGTIFF support, almost as if it's still pushing the 1.9.2 system version that does not contain support.

I also ran an strace, and after initially finding it wasn't actually finding the libtiff.so (it was looking for .3 instead of .5), I created a symlink and directed it there. So it's definitely using the custom build libtiff and libgeotiff at runtime.

So, that brings me back to the question. Is there a hidden variable somewhere I'm not aware of getting used? Or is there a way to test for BIGTIFF support after a build besides it failing? I know non-standard installs are always a unique challenge, but nothing I've done so far allows for BIGTIFF use in the merge, and the merges fail at the size of system memory.

Best Answer

Ok, so the problem here was within the build of libgeotiff. The library did not get built properly, and from running "nm libgeotiff.so", it was missing the symbols from GTIFAllocDefn and GTIFFreeDefn.

The geotiff library had, apparently, built against the system installed version due to a mismatch of the library name. So while libtiff built with bigtiff support, libgeotiff did not. But since GDAL was apparently looking at libtiff to say it had BIGTIFF support, but not libgeotiff, it failed to build properly, despite claiming it configured properly.

I can't definitively isolate what happened there to repeat it, but rebuilding libgeotiff followed by gdal seems to have done the trick, and bigtiff support is now working.

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