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Summarize area by class

Source: R/dft_rast_summarize.R
dft_rast_summarize.Rd

Compute area and percentage by class for a categorical raster, optionally across multiple years.

Usage

dft_rast_summarize(x, class_table = NULL, source = "io-lulc", unit = "ha")

Arguments

x

A terra::SpatRaster or a named list of SpatRasters. When a named list, each name is used as the year column in the output.

class_table

A tibble with columns code, class_name, color. When NULL, loaded via dft_class_table() using source.

source

Character. Used to load a shipped class table when class_table is NULL. One of "io-lulc" or "esa-worldcover".

unit

Character. Area unit for the area column. One of "ha" (default), "km2", or "m2".

Value

A tibble with columns:

  • year (character, only when x is a named list)

  • code (integer)

  • class_name (character)

  • color (character, hex)

  • n_cells (integer)

  • area (numeric, in requested unit)

  • pct (numeric, percentage of total non-NA cells)

Examples

r <- terra::rast(system.file("extdata", "example_2020.tif", package = "drift"))
dft_rast_summarize(r, source = "io-lulc", unit = "ha")
#> # A tibble: 6 × 6
#>    code class_name color   n_cells  area   pct
#>   <int> <chr>      <chr>     <int> <dbl> <dbl>
#> 1     1 Water      #419bdf    1089 10.9   8.85
#> 2     2 Trees      #397d49    5542 55.4  45.0 
#> 3     5 Crops      #e49635     147  1.47  1.19
#> 4     7 Built Area #c4281b      10  0.1   0.08
#> 5     9 Snow/Ice   #a8ebff     185  1.85  1.5 
#> 6    11 Rangeland  #e3e2c3    5338 53.4  43.4