[GRASS-user] mapcalc NULL issue

[Carlos "Guâno" Grohmann]

Hello all.

I have two rasters (SRTM_V2), one has data on the continental area,
with zero values in the ocean. The other (SRTM_30 PLUS) has values for
all region. I'd like to patch them, using r.mapcalc, like this:
if srtmv2==0 OR srtmv2==NULL, then use value from srtm30plus, else srtmv2.

I tried this in mapcalc:

test=if(A==0||isnull(A), B,A)

but it didn't work. the result was the same as test=if(A==0, B,A).

So how can I manage to get the condition for zero and null at the same
time? I mean, I can do this in a single operation, right? Or do I need
to make two operations?

cheers

-- 
+-----------------------------------------------------------+
              Carlos Henrique Grohmann - Guano
  Geologist M.Sc  - Doctorate Student at IGc-USP - Brazil
Linux User #89721  - carlos dot grohmann at gmail dot com
+-----------------------------------------------------------+
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