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Convert a Categorical Raster to a Value Raster

Source: R/cat_to_val.R
cat_to_val.Rd

Use a categorical raster's RAT to convert it to a continuous raster

Usage

cat_to_val(r, which = 2)

Arguments

r

A categorical raster with a RAT (returned by levels(r)[[1]]), whose first column contain an entry for every factor level present in the raster. At least one of the subsequent columns should contain numeric values to which each level should be converted.

which

An integer or character string giving the index or name of the column in r's RAT with the numerical values to which each value in r should be mapped. Default value is 2.

Value

A continuous raster with each category level in r

replaced by its corresponding value.

Author

Joshua O'Brien

Examples

r_cat <- raster(matrix(c(2, 2, 2, 1), ncol = 2))
levels(r_cat) <- data.frame(ID = c(1, 2),
                            VAL1 = c(0.1, 200),
                            VAL2 = c(33, 44))

## Second column of RAT is used by default
r_con1 <- cat_to_val(r_cat)
as.matrix(r_con1)
#>      [,1]  [,2]
#> [1,]  200 200.0
#> [2,]  200   0.1

## Use 'which=' argument for conversion to another RAT column
r_con2 <- cat_to_val(r_cat, which = "VAL2")
as.matrix(r_con2)
#>      [,1] [,2]
#> [1,]   44   44
#> [2,]   44   33