[GRASS-dev] r.out.gdal -f flag clarification

[Markus Metz]

Patton, Eric wrote:
>
> Hi,
>
> I trying to decipher the meaning of the description of the r.out.gdal 
> –f flag. Currently, it reads:
>
> “Force raster export also if data loss may occur”
>
The long description would be that the -f flag does not have any effect 
if no data loss occurs. Only if the export settings would result in 
actual data loss, the -f flag has an effect and allows for the creation 
of a raster that is not an exact (as exact as possible given the chosen 
export format) representation of the raster map to be exported using the 
current computational region. Without the -f flag, if any of the tests 
is not passed, an error message is issued describing the problem and the 
module exits without exporting. The -f flag allows to export a raster 
even if some of the tests are not passed and warnings are issued instead 
of errors.
>
> I take it it should read “Force raster export (note: data loss may occur)”
>
That sounds a bit like the -f flag would cause the module to export a 
raster somehow differently than without the -f flag which is not the 
case, the -f flag only overrides tests for data loss. IOW, if a raster 
could only be exported with the -f flag set, data loss will have 
occurred, not may have occurred.

The idea was to run r.out.gdal first without the -f flag, if it 
complains, change export settings or override with -f flag.

I guess the documentation as well as the warning and error messages 
could do with some improvement/clarification?

Markus M