[GRASS-dev] Re: GRASS 7 status overview

[Glynn Clements]

Michael Barton wrote:

> >> r.external.out and r.colors.out do not generate the GUI when run from
> >> the command line.
> > 
> > Both generate a GUI when run with --ui. r.external.out doesn't have
> > any required arguments (mainly due to -f), while r.colors.out has a
> > bug:
> 
> It is unclear how r.external.out works. Does it make a GDAL-compatible
> file appear as a GRASS raster in a mapset? If so, shouldn't this be
> r.external.in? (i.e., it makes an external raster usable by GRASS)

r.external.out causes new raster maps to be created as files via GDAL.

Whereas r.external turns a specific file into a GRASS raster map,
r.external.out enables a mode whereby all new rasters are created as
files via GDAL.

It creates a key-value file named "GDAL" in the mapset directory
containing various parameters (output directory, file format, creation
parameters). If this file is present, Rast_open_*_new() and
Rast_put_*_row() go via GDAL.

> > Also, ximgview should be superseded by wximgview (except, wximgview
> > currently doesn't build on Windows, for the same reason as xganim and
> > the vdigit and nviz modules, i.e. trying to link against wxWidgets
> > crashes "ld").
> 
> OK wximgview works. I guess I misunderstood what this did. So it's to
> offer a way to view graphics created by d.* commands?

Yes. Specifically, it continually refreshes the display from the
contents of the image file (which must be written using
GRASS_PNG_MAPPED=TRUE, so that the file is modified in place, never
truncated), providing a rough substitute for XDRIVER (i.e. run d.*
commands from the command line, observe the result in a window).

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