[GRASSLIST:6382] r.mapcalc growing area

[Māris Nartišs]

Hi all,

today I realised that Im too dubm to use r.mapcalc :) r.mapcalc is too
powerfull tool for my small brain.

I have two raster maps map1 and map2. map1 covers whole teritory, but
map2 contains only one cell. I want to modify map2  in following way:
if map2 cell not null -> calculate new value from map1 and also
calculate (and assign) new values to all 8 neighborhood cells (i.e.
[1,1], [-1,0] etc.)

I cant find way how to assign new values to all neighborhood cells and
do it only if they are one cell far from map2 cell with value. As
calculating new values takes aditional checks, I always fail in logic.
:(

Some aditional qs:
1) can ! be used to reverse things (ie. !isnull(x) to chek if x is not null)?
2) is any way to get some feedback from r.mapcalc was any cell
affected by last command/action? It s need to know if there is need to
do additional calculating pass ower data.

tnx for any ideas,
Maris.