Summary metrics on a single raster

Summary functions that return a scalar when passed with a portion of raster. Typically passed to MHM.

Usage

richness(x, ...)

simpson(x, ...)

shannon(x, ...)

shannon_evenness(x, ...)

contagion(x, ...)

contagion_cppr(x, ...)

shannon_evenness_cppr(x, ...)

simpson_cppr(x, ...)

shannon_cppr(x, ...)

Arguments

x

a fraction of a SpatRaster raster

...

additional parameters, used to collect terra::focal own passing through ...

Value

numeric the index of interest

Details

For now on, some function have a cpp counterpart. The R implementation will likely be removed soon. So far we maintain both for the sake of testing. When a _cppr version exists, use it!

• richness simply returns the total number of unique classes (only makes sense on categorical landscapes)

• simpson/simpson_cppr is the Simpson's diversity index

• shannon/shannon_cppr is the Shannon's diversity index

• shannon/shannon_cppr optimized version in cpp

• shannon_evenness/shannon_evenness_cppr is the Shannon's evenness index

• kappa_index/kappa_index_cppr is Kappa index

• student_p is the p value from a Student's test

• contagion/contagion_cppr is the contagion index (Riitters, 1996) and also from MHM paper (only makes sense on categorical landscapes)

Examples

set.seed(2329) # for reproducibility
x <- sample(1:3, size=49, replace=TRUE, prob=c(0.1, 0.1, 1))  # unbalanced vector
table(x)
#> x
#>  1  2  3 
#>  3  7 39 
x %>% richness()
#> [1] 3
x %>% simpson()
#> [1] 0.3423574
x %>% simpson_cppr()
#> [1] 0.3423574
x %>% shannon()
#> [1] 0.6306752
x %>% shannon_cppr()
#> [1] 0.6306752
x %>% shannon_evenness()
#> [1] 0.5740653
x %>% shannon_evenness_cppr()
#> [1] 0.5740653
x %>% contagion()
#> [1] 42.00754
x %>% contagion_cppr()
#> [1] 42.00754