Rescale values to a new range
rescale(x, to, from, ...)
# S3 method for class 'numeric'
rescale(x, to = c(0, 1), from = range(x, na.rm = TRUE, finite = TRUE), ...)
# S3 method for class 'RasterLayer'
rescale(
x,
to = c(0, 1),
from = range(getValues(x), na.rm = TRUE, finite = TRUE),
...
)
# S3 method for class 'SpatRaster'
rescale(
x,
to = c(0, 1),
from = range(values(x), na.rm = TRUE, finite = TRUE),
...
)A new object whose values have been rescaled.
Objects with values that are all equal (e.g., all zeroes) will be returned as-is.
This behaviour differs from scales:rescale which would return a value of 0.5.
rescale(50, from = c(0, 100), to = c(0, 1)) ## 0.5
#> [1] 0.5
x <- 0:100
rescale(x) ## defaults to new range [0,1]
#> [1] 0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10 0.11 0.12 0.13 0.14
#> [16] 0.15 0.16 0.17 0.18 0.19 0.20 0.21 0.22 0.23 0.24 0.25 0.26 0.27 0.28 0.29
#> [31] 0.30 0.31 0.32 0.33 0.34 0.35 0.36 0.37 0.38 0.39 0.40 0.41 0.42 0.43 0.44
#> [46] 0.45 0.46 0.47 0.48 0.49 0.50 0.51 0.52 0.53 0.54 0.55 0.56 0.57 0.58 0.59
#> [61] 0.60 0.61 0.62 0.63 0.64 0.65 0.66 0.67 0.68 0.69 0.70 0.71 0.72 0.73 0.74
#> [76] 0.75 0.76 0.77 0.78 0.79 0.80 0.81 0.82 0.83 0.84 0.85 0.86 0.87 0.88 0.89
#> [91] 0.90 0.91 0.92 0.93 0.94 0.95 0.96 0.97 0.98 0.99 1.00
rescale(x, c(-1, 1))
#> [1] -1.00 -0.98 -0.96 -0.94 -0.92 -0.90 -0.88 -0.86 -0.84 -0.82 -0.80 -0.78
#> [13] -0.76 -0.74 -0.72 -0.70 -0.68 -0.66 -0.64 -0.62 -0.60 -0.58 -0.56 -0.54
#> [25] -0.52 -0.50 -0.48 -0.46 -0.44 -0.42 -0.40 -0.38 -0.36 -0.34 -0.32 -0.30
#> [37] -0.28 -0.26 -0.24 -0.22 -0.20 -0.18 -0.16 -0.14 -0.12 -0.10 -0.08 -0.06
#> [49] -0.04 -0.02 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18
#> [61] 0.20 0.22 0.24 0.26 0.28 0.30 0.32 0.34 0.36 0.38 0.40 0.42
#> [73] 0.44 0.46 0.48 0.50 0.52 0.54 0.56 0.58 0.60 0.62 0.64 0.66
#> [85] 0.68 0.70 0.72 0.74 0.76 0.78 0.80 0.82 0.84 0.86 0.88 0.90
#> [97] 0.92 0.94 0.96 0.98 1.00
f <- system.file("external/test.grd", package = "raster")
r <- raster::raster(f)
rescale(r) ## defaults to new range [0,1]
#> class : RasterLayer
#> dimensions : 115, 80, 9200 (nrow, ncol, ncell)
#> resolution : 40, 40 (x, y)
#> extent : 178400, 181600, 329400, 334000 (xmin, xmax, ymin, ymax)
#> crs : +proj=sterea +lat_0=52.1561605555556 +lon_0=5.38763888888889 +k=0.9999079 +x_0=155000 +y_0=463000 +datum=WGS84 +units=m +no_defs
#> source : memory
#> names : test
#> values : 0, 1 (min, max)
#>
rescale(r, c(-1, 1))
#> class : RasterLayer
#> dimensions : 115, 80, 9200 (nrow, ncol, ncell)
#> resolution : 40, 40 (x, y)
#> extent : 178400, 181600, 329400, 334000 (xmin, xmax, ymin, ymax)
#> crs : +proj=sterea +lat_0=52.1561605555556 +lon_0=5.38763888888889 +k=0.9999079 +x_0=155000 +y_0=463000 +datum=WGS84 +units=m +no_defs
#> source : memory
#> names : test
#> values : -1, 1 (min, max)
#>
f <- system.file("ex/test.grd", package = "terra")
r <- terra::rast(f)
rescale(r) ## defaults to new range [0,1]
#> class : SpatRaster
#> size : 115, 80, 1 (nrow, ncol, nlyr)
#> resolution : 40, 40 (x, y)
#> extent : 178400, 181600, 329400, 334000 (xmin, xmax, ymin, ymax)
#> coord. ref. : +proj=sterea +lat_0=52.1561605555556 +lon_0=5.38763888888889 +k=0.9999079 +x_0=155000 +y_0=463000 +datum=WGS84 +units=m +no_defs
#> source(s) : memory
#> varname : test
#> name : test
#> min value : 0
#> max value : 1
rescale(r, c(-1, 1))
#> class : SpatRaster
#> size : 115, 80, 1 (nrow, ncol, nlyr)
#> resolution : 40, 40 (x, y)
#> extent : 178400, 181600, 329400, 334000 (xmin, xmax, ymin, ymax)
#> coord. ref. : +proj=sterea +lat_0=52.1561605555556 +lon_0=5.38763888888889 +k=0.9999079 +x_0=155000 +y_0=463000 +datum=WGS84 +units=m +no_defs
#> source(s) : memory
#> varname : test
#> name : test
#> min value : -1
#> max value : 1