[Qgis-developer] Huge TIFF files - problem

[Alex Mandel]

On 12/08/2014 04:39 PM, Giovanni Manghi wrote:
>> Hi,
>> I have got a problem with TIFF files.
>> Today I was performing a rastercalculation ? two smaller files was suddenly 122 GB ? and my computer ran out of free space.
>> And this afternoon my students georeferenced a jpg, and ended up with 24 GB map.
>>
>> What am I doing wrong?
> 
> 
> Hi Lene,
> I'm not sure if it is enough to justify such huge output files, but
> most of the tools in the "raster" menu just output always float64
> tiffs, that certainly contribute to make often bigger than the
> necessary. This has been fixed in Processing where most of the gdal
> tools now have an option to choose the type of geotiff for the output.
> 
> cheers
> 

That probably is the answer, not only float64 but no compression.
GeoTiff ideally would be a more appropriate storage based on the inputs
and calculation but also use Deflate or LZW compression. Seems to me a
reasonable default to use one of the lossless compression methods. Not
much to be done about the storage type though other than offer users
options when saving Tiffs where possible.

Thanks,
Alex