[GRASS5] r.patch and NULL data

[Markus Neteler]

Hi,

at time I face the problem that r.patch does not work as I
expect...

Idea: patch a converted sites map to a underlying raster map
in this small data set (11 kb):

http://grass.itc.it/statsgrass/maas_grass_location.tar.gz
Maas river bank soil contamination (UTM)

What I did:

grass5 ~/grassdata/maas/user1/
1. s.to.rast in=Zn out=zn
2. r.patch zn,maasbank out=fin

result only contains the raster cells from zn, the maasbank
area is not visible (fin = zn).

Also
 r.mapcalc fin="if(isnull(zn),maasbank,zn)"
doesn't help.

Is it my mistake (which)?

Thanks for any advice,

 Markus