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

GRASS GRASS developer
,
1

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”

I take it it should read “Force raster export (note: data loss may occur)”

?

–

Eric Patton

Technologist, Geo-Spatial Data Services

Natural Resources Canada

Geological Survey of Canada (Atlantic)

Bedford Institute of Oceanography

1 Challenger Drive (P.O. Box 106)

Dartmouth, Nova Scotia, B2Y 4A2

Telephone: (902) 426-7732

Facsimile: (902) 426-4104

Email: epatton@nrcan.gc.ca

2

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

3

Markus M:

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

Thanks for the info. I'll update the docs a little later today.

Cheers,

--
Eric

4

Patton, Eric wrote:

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"

I take it it should read "Force raster export (note: data loss may
occur)"

Changing "also if" to "even if" is probably sufficient.

--
Glynn Clements <glynn@gclements.plus.com>

5

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

Markus M

Done in develbranch_6 and trunk.

--
Eric Patton