Frequency table — freq • terra

Frequency table of the values of a SpatRaster. NAs are not counted unless value=NA.

You can provide a SpatVector or additional SpatRaster to define zones for which to do tabulations.

Usage

# S4 method for class 'SpatRaster'
freq(x, digits=0, value=NULL, bylayer=TRUE, usenames=FALSE, 
    zones=NULL, wide=FALSE, touches=FALSE)

Arguments

x: SpatRaster
digits: integer. Used for rounding the values before tabulation. Ignored if NA
value: numeric. An optional single value to only count the number of cells with that value. This value can be NA
bylayer: logical. If TRUE tabulation is done by layer
usenames: logical. If TRUE layers are identified by their names instead of their numbers Only relevant if bylayer is TRUE
zones: SpatRaster or SpatVector to define zones for which the tabulation should be done
wide: logical. Should the results by "wide" instead of "long"?
touches: logical. If TRUE, all cells touched by lines or polygons will be included, not just those on the line render path, or whose center point is within the polygon. Only relevant if zones is a SpatVector

Value

A data.frame with 3 columns (layer, value, count) unless bylayer=FALSE in which case adata.frame with two columns is returned (value, count).

Examples

r <- rast(nrows=10, ncols=10)
set.seed(2)
values(r) <- sample(5, ncell(r), replace=TRUE)

freq(r)
#>   layer value count
#> 1     1     1    27
#> 2     1     2    15
#> 3     1     3    17
#> 4     1     4    17
#> 5     1     5    24

x <- c(r, r/3)
freq(x, bylayer=FALSE)
#>   value count
#> 1     0    27
#> 2     1    76
#> 3     2    39
#> 4     3    17
#> 5     4    17
#> 6     5    24
freq(x)
#>   layer value count
#> 1     1     1    27
#> 2     1     2    15
#> 3     1     3    17
#> 4     1     4    17
#> 5     1     5    24
#> 6     2     0    27
#> 7     2     1    49
#> 8     2     2    24

freq(x, digits=1)
#>    layer value count
#> 1      1   1.0    27
#> 2      1   2.0    15
#> 3      1   3.0    17
#> 4      1   4.0    17
#> 5      1   5.0    24
#> 6      2   0.3    27
#> 7      2   0.7    15
#> 8      2   1.0    17
#> 9      2   1.3    17
#> 10     2   1.7    24
freq(x, digits=-1)
#>   layer value count
#> 1     1     0    76
#> 2     1    10    24
#> 3     2     0   100

freq(x, value=5)
#>   layer value count
#> 1     1     5    24
#> 2     2     5     0