[GRASS-user] raster history logs

[Glynn Clements]

Nikos Alexandris wrote:

> Why isn't the raster history log (of any raster) similar with a vector's
> history log?
> 
> Whenever I create a subset of a map with r.mapcalc, its pre-r.mapcalc
> history is gone. Is it not a good idea to keep all actions logged?

The problem is that a map created by r.mapcalc can based upon an
unlimited number of input maps. Also, actually identifying which maps
the output is based upon isn't straightforward. E.g. the defining
expression can use variables whose value depends upon some other map,
and identifying such dependencies could be quite complex.

For modules which perform a straightforward transformation of a single
input map, it wouldn't be particularly hard to include the history of
the original input map.

There's still the issue that the history is limited to 50 lines, so
complex sequences of commands will eventually result in the earlier
history getting lost.

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