[GRASS-user] mapcalc and cell coordinates

[G. Allegri]

> r.mapcalc brol3=if(y()<=9521600 && x()<=427000,1,null())
>
> but this doesn't:
>
> r.mapcalc brol3=if(y()==9521600 && x()==427000,1,null())
>
> which raises the issue of precision of the coordinates...

So, it's possible to check above a range of coordinates but not on a
specific one...
But I don't understand a thing:
r.mapcalc/coor.c uses G_northing_to_row() and G_easting_to_row() as
well as r.what, for example. Why the issue about precision doesn't
happen in this case?