gainoffset: Gain and offset of values on file

In raster: Geographic Data Analysis and Modeling

Gain and offset of values on file

Description

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 Arith-methods.

Usage

gain(x)
gain(x) <- value
offs(x)
offs(x) <- value

Arguments

x	Raster* object
value	Single numeric value

Value

Raster* object or numeric value(s)

Examples

 
r <- raster(system.file("external/test.grd", package="raster"))
gain(r)
offs(r)
r[1505:1510]
gain(r) <- 10
offs(r) <- 5
r[1505:1510]

raster documentation built on Oct. 3, 2024, 1:08 a.m.