[GRASS-dev] [GRASS GIS] #3667: Add an option to add grey color scale to r.in.gdal imports

#3667: Add an option to add grey color scale to r.in.gdal imports
---------------------------+-------------------------
Reporter: pierreroudier | Owner: grass-dev@…
     Type: enhancement | Status: new
Priority: normal | Milestone:
Component: Default | Version: unspecified
Keywords: | CPU: Unspecified
Platform: Unspecified |
---------------------------+-------------------------
At the moment `r.in.gdal` automatically affects the `viridis` colour
palette to any raster layer imported.

I think that's a good thing, and for single layer rasters it corresponds
to best modern practice.

It is however slightly annoying when importing imagery, and necessitate to
loop through the bands with `r.colors layer.i col=grey`.

I think the best of both worlds could be achieved by adding a flag `-g` to
`r.in.gdal` that would force the colour palette to be `grey`.

Thus:

{{{
r.in.gdal ./path/to/foo.tif out=foo
}}}

would use `viridis`, while:

{{{
r.in.gdal -g ./path/to/bar.tif out=bar
}}}
would use `grey`.

--
Ticket URL: <https://trac.osgeo.org/grass/ticket/3667&gt;
GRASS GIS <https://grass.osgeo.org>

#3667: Add an option to add grey color scale to r.in.gdal imports
----------------------------+-----------------------------------------
  Reporter: pierreroudier | Owner: grass-dev@…
      Type: enhancement | Status: new
  Priority: normal | Milestone: 7.8.0
Component: Display | Version: 7.4.1
Resolution: | Keywords: d.rast, default color table
       CPU: All | Platform: All
----------------------------+-----------------------------------------
Changes (by mmetz):

* component: Default => Display
* platform: Unspecified => All
* version: unspecified => 7.4.1
* milestone: => 7.8.0
* keywords: => d.rast, default color table
* cpu: Unspecified => All

Comment:

Replying to [ticket:3667 pierreroudier]:
> At the moment `r.in.gdal` automatically affects the `viridis` colour
palette to any raster layer imported.

It is not `r.in.gdal` but the raster library that assigns `viridis`, the
default color table, if a raster does not have a color table assigned.
>
> I think that's a good thing, and for single layer rasters it corresponds
to best modern practice.
>
> It is however slightly annoying when importing imagery, and necessitate
to loop through the bands with `r.colors layer.i col=grey`.
>
> I think the best of both worlds could be achieved by adding a flag `-g`
to `r.in.gdal` that would force the colour palette to be `grey`.

`r.in.gdal` assigns a color table only if color table information is
available in the input metadata.

Thus the solution would be to either use `grey` as default for CELL maps
(in the raster library), or specifically assign a color table with
`r.colors`.

Anyway, this is not an issue of `r.in.gdal`.

--
Ticket URL: <https://trac.osgeo.org/grass/ticket/3667#comment:1&gt;
GRASS GIS <https://grass.osgeo.org>