[GRASS-user] map algebra logical operators on DCELL rasters not admitted? maybe docs should outline it

[Moritz Lennert]

On 20/10/15 09:44, Moritz Lennert wrote:
> On 19/10/15 21:16, Glynn Clements wrote:
>>
>> G. Allegri wrote:
>>
>>> Doing a logical operation with a DCELL raster within an if(x,a) statement
>>> produces an error: "Incorrect argument types to function bitand()".
>>
>> First, you're confusing bitwise operators and logical operators. & and
>> | are bitwise operators, while && and || (and &&& and |||) are logical
>> operators.
>>
>> Second, both bitwise and logical operators only work on integer
>> values. If you want to use floating-point values as boolean values,
>> you need to explicitly convert them to integers (either via int(x) or
>> round(x), or x==0.0, or abs(x)<1e-30, or whatever).
>
> ???
>
> On my grass71 and grass64release, these work (using NC demo data set):
>
> r.mapcalc "test = if(elevation == 100.0, 1)"
> r.mapcalc "test = if(elevation > 100.0, 1)"
>
> where elevation is FCELL.

Sorry, forget that. I missed the "logical" part...

Moritz