[GRASS-user] Null or 0?

ALT SHN i.geografica at alt-shn.org
Sat Feb 4 21:03:44 EST 2012


I have a technichal doubt. I used* v.to.rast.constant *to tranform a line
vector layer to raster. This meant i have a raster with NULL values.
The output raster is to be used in map algebra operations.

So my question is:  Is it advisable to set the Null cells to 0? I know
r.calc works with NULL values, and I know that NULL is not the same as 0,
however I never understood what difference does it make if any. Considering
these two scenarios what do I win and what do I loose?

Any enlightening will be very aprecciated!


André Mano
Associação Leonel Trindade

Apartado 25 2564-909 Torres Vedras Portugal
Sede e Biblioteca: rua Cavaleiros da Espora Dourada, 27A 2560 Torres Vedras

Laboratório de Paleontologia e Paleoecologia: Polígono Industrial do Alto
do Ameal 2565-641 Ramalhal
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