[GRASS-dev] [GRASS GIS] #3130: r.out.gdal: add alpha channel support

[GRASS GIS]

#3130: r.out.gdal: add alpha channel support
--------------------------+---------------------------------
  Reporter:  neteler      |      Owner:  grass-dev@…
      Type:  enhancement  |     Status:  new
  Priority:  normal       |  Milestone:  7.2.0
 Component:  Docs         |    Version:  svn-releasebranch72
Resolution:               |   Keywords:  r.out.gdal, alpha
       CPU:  Unspecified  |   Platform:  Unspecified
--------------------------+---------------------------------
Changes (by neteler):

 * keywords:  r.out.gdal => r.out.gdal, alpha
 * component:  Raster => Docs


Comment:

 Replying to [comment:5 mmetz]:
 > Replying to [comment:4 neteler]:
 > > Still I am not sure if it now better to use `r.rescale` or the `#`
 operator of `r.mapcalc` with some formula in order to "free up" the 0
 value for paving the way of exporting with alpha as above?
 >
 > This is about exporting RGB data, not GIS data, therefore the `#`
 operator of `r.mapcalc` needs to be used. The result is a regular image
 (like a screenshot) that can be displayed by any simple image viewer
 coming with your OS and/or desktop environment. When exporting, do you
 want to provide something like a screenshot or the actual data?

 Yes exactly. Here it is for showing the data in a Web system. I have taken
 liberty to write up an example for the manual page from your comments,
 r69162. Thanks for the explanations.

 (an example backport needs r69128 and r69131 - they works nicely for me in
 a local 7.2.svn backport).

--
Ticket URL: <https://trac.osgeo.org/grass/ticket/3130#comment:6>
GRASS GIS <https://grass.osgeo.org>