[GRASS5] [bug #4368] (grass) r.blend: overwrites the output instead of 'Error: map exists.'

[Glynn Clements]

Markus Neteler wrote:

> > Subject: r.blend: overwrites the output instead of 'Error: map exists.'
> 
> This happens because r.mapcalc is used which is not testing for
> existing maps.

This happens because the r.blend script uses the "old" tag for its
output maps, so G_parser() doesn't check whether they already exist.

FWIW, I can add an explicit check to r.mapcalc to prevent overwriting,
if that is considered desirable.

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