These functions can be used to get or set the gain and offset parameters used to transform values when reading them from a file. The gain and offset parameters are applied to the raw values using the formula below:
value <- value * gain + offset
The default value for gain is 1 and for offset is 0. 'gain' is sometimes referred to as 'scale'.
Note that setting gain and/or offset are intended to be used with values that are stored in a file. For a Raster* object with values in memory, assigning gain or offset values will lead to the inmediate computation of new values; in such cases it would be clearer to use
gain(x) gain(x) <- value offs(x) offs(x) <- value
Single numeric value
Raster* object or numeric value(s)
r <- raster(system.file("external/test.grd", package="raster")) gain(r) #>  1 offs(r) #>  0 r[1505:1510] #>  447.7600 439.2610 435.7418 390.6812 364.3720 372.6429 gain(r) <- 10 offs(r) <- 5 r[1505:1510] #>  447.7600 439.2610 435.7418 390.6812 364.3720 372.6429