[GIS] Saving raster to BigTIFF in QGIS

bigtifflarge datasetsqgisraster

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?

Best Answer

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.

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[GIS] Opening a BigTIFF file in Python

A couple of things here:

Firstly don't set gdata to None until you are COMPLETELY done with that raster, data will return a broken dataset if you do. Please see for a more detailed explanation: https://trac.osgeo.org/gdal/wiki/PythonGotchas

Next thing uninstall gdal using pip then reinstall it using the .whl file from here: https://www.lfd.uci.edu/~gohlke/pythonlibs/#gdal Let me know if you need an explanation how to do this.

Also 90MB is -tiny- it shouldn't need to be a bigtiff till it goes over 4GB when compressed.

Also just to make everything a bit faster/memory efficient:

from osgeo import gdal, osr, ogr

def get_value_at_point(rasterfile, pos):
    gdal.UseExceptions()
    gdata = gdal.Open(rasterfile)
    gt = gdata.GetGeoTransform()
    x = int((pos[0] - gt[0])/gt[1])
    y = int((pos[1] - gt[3])/gt[5])

    data = gdata.ReadAsArray(x,y).astype(np.float) #This will only load the cell you want
    return data

[GIS] How to write BIGTIFF raster files with rasterio

I tried with the following and it worked fine:

with rasterio.open(out_path, 
                   "w", 
                   **out_meta, 
                   tiled=True, 
                   blockxsize=256, 
                   blockysize=256, 
                   BIGTIFF='YES') as dest:

Best Answer

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[GIS] Opening a BigTIFF file in Python

[GIS] How to write BIGTIFF raster files with rasterio

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