Using QGIS 3.4, I am trying to merge multiple DEMs downloaded from the National Map Viewer that are in ArcGRID format (Arc/Info Binary Grid). The output will be a large file so I can't use any of the formats limited to 2 or 4GB in size. I would like to save it as a BigTIFF but I don't know how to distinguish that from a TIFF in the merge raster dialogue box. I tried to save it as TIFF but it failed as file was over 4GB.

How do I save merged rasters as BigTIFF or, if this is not possible, how do I merge rasters to produce the smallest possible file size?

  • Maybe you could use a VRT file created with gdalbuildvrt? Commented Nov 10, 2018 at 1:38

1 Answer 1


See the command that the tool is generating to the "GDAL/OGR console call" box. Read GeoTIFF driver documentation https://www.gdal.org/frmt_gtiff.html and edit the command by adding one more option -co BIGTIFF=YES for forcing BigTIFF.

enter image description here

  • Thank you 30184. I usually use ArcMap, not Q, and I am not sure how I access the tools command parameters?
    – sparky
    Commented Nov 14, 2018 at 16:06
  • To be more specific, I don't see how I can edit them. When I click in the GDAL/OGR console call, it doesn't allow me to edit the command.
    – sparky
    Commented Nov 14, 2018 at 16:13
  • 2
    Press + in the Additional creation options panel and write "bigtiff" as a name and "yes" as a value. The command should update.
    – user30184
    Commented Nov 14, 2018 at 20:06
  • I added also a screenshot.
    – user30184
    Commented Nov 15, 2018 at 7:31

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