Q:

How to decrease GeoTIFF file size by eliminating or negating the blackfill?

I have a 5 band, 16-bit orthorectified GeoTIFF from a satellite image that contains a significant amount of blackfill and has a file size of over 21GB. I would like to decrease the file size by eliminating or negating the blackfill. I have attempted to use the SPARSE_OK option in GDAL as such:
gdal_translate -of GTiff -co "BIGTIFF=YES" -co "SPARSE_OK=TRUE" -co "TILED=YES" input.tif output.tif
This has had no effect on the file size. Is my understanding of how SPARSE_OK works incorrect or is there a potential problem with the SPARSE_OK option? Is there a better way of reducing the file size? I have tried "COMPRESS=DEFLATE", which works, but then the product is veryyyy slow is loading into the viewing software. 

A:

COMPRESS=LZW should give you better load times and equivalent packing ratio as DEFLATE.  See if that helps?

