Running gdalinfo on both files reveals a 'nodata' value of -9999. When I view the data as individual files in QGIS, the 'nodata' regions are confirmed as 'nodata' or '-9999' and are rendered transparent.
No matter which variation of merge I run, those regions that once contained 'nodata' or '-9999' are converted to '0' and the nodata value is not retained after the merge. When I load the test_merge_wnodata.tif into QGIS, those regions once containing 'nodata',
are now filled with 0 and rendered as such.
Maybe this is a bug or am I using gdal_merge.py improperly.
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