Change raster range values from 0/100 to 1/100-CodePudding

I have a raster layer ranging from 0 (minimum) to 100 (maximum) and I would like to change its values to range from 1 to 100. It is important that data do not change, basically I want to have the same raster but with a different range of values.

I can work both on R and QGIS.

Thanks everyone for help! :)

CodePudding user response：

Let's take a simple example in R, where we have a raster with values ranging between 0 and 100, as we can see by the min value and max value fields:

library(raster)
#> Loading required package: sp

r <- raster(matrix(c(0, 25, 100, 15, 0, 22, 86, 54, 67), nrow = 3))

r
#> class      : RasterLayer 
#> dimensions : 3, 3, 9  (nrow, ncol, ncell)
#> resolution : 0.3333333, 0.3333333  (x, y)
#> extent     : 0, 1, 0, 1  (xmin, xmax, ymin, ymax)
#> crs        : NA 
#> source     : memory
#> names      : layer 
#> values     : 0, 100  (min, max)

To overwrite the 0 values with 1s, we can do

r[][r[] == 0] <- 1

Resulting in

r
#> class      : RasterLayer 
#> dimensions : 3, 3, 9  (nrow, ncol, ncell)
#> resolution : 0.3333333, 0.3333333  (x, y)
#> extent     : 0, 1, 0, 1  (xmin, xmax, ymin, ymax)
#> crs        : NA 
#> source     : memory
#> names      : layer 
#> values     : 1, 100  (min, max)

^{Created on 2023-01-24 with}

r[] = rescale(r[], to=c(1,100))
plot(r)