[GRASS-user] r.mapcalculator and r.mapcalc

[Luiz Andrade]

Thanks!
Can you help me with another thing?
My images have 15m pixels, after processing in r.mapcalc and exporting they have 62m pixels. How can I solve this?

Thanks again

Regards,
Luiz Claudio




> Em 20 de fev de 2017, à(s) 18:42, Helmut Kudrnovsky <hellik at web.de> escreveu:
> 
>> 1 - Why wasn’t r.mapcalculator ported to grass7? It is great to use it from
> within QGIS.
> 
> can't answer this one
> 
>> My r.mapcalc outputs int32 rasters (I want float32). Is there a way to
> choose the output type?
> 
> from the manual [1]
> 
> ------------------------
> [...]
> Functions
> The functions currently supported are listed in the table below. The type of
> the result is indicated in the last column. F means that the functions
> always results in a floating point value, I means that the function gives an
> integer result, and * indicates that the result is float if any of the
> arguments to the function are floating point values and integer if all
> arguments are integer. 
> 
> [...]
> Floating point values in the expression
> Floating point values in the expression are handled in a special way. With
> arithmetic and logical operators, if either operand is float, the other is
> converted to float and the result of the operation is float. This means, in
> particular that division of integers results in a (truncated) integer, while
> division of floats results in an accurate floating point value. With
> functions of type * (see table above), the result is float if any argument
> is float, integer otherwise.
> 
> Note: If you calculate with integer numbers, the resulting map will be
> integer. If you want to get a float result, add the decimal point to integer
> number(s).
> 
> If you want floating point division, at least one of the arguments has to be
> a floating point value. Multiplying one of them by 1.0 will produce a
> floating-point result, as will using float():
> 
>      r.mapcalc "ndvi = float(lsat.4 - lsat.3) / (lsat.4 + lsat.3)"
> [...]
> ------------------------
> 
> HTH
> 
> [1] https://grass.osgeo.org/grass73/manuals/r.mapcalc.html
> 
> 
> 
> -----
> best regards
> Helmut
> --
> View this message in context: http://osgeo-org.1560.x6.nabble.com/r-mapcalculator-and-r-mapcalc-tp5308738p5308742.html
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