Diversity metrics

A range of functions to calculate well known landcover diversity metrics

Usage

# S3 method for winmove
shdi(x, lc_class, d, type, ...)

# S3 method for numeric
shdi(x, lc_class, ...)

# S3 method for winmove
shei(x, lc_class, d, type, ...)

# S3 method for numeric
shei(x, lc_class, ...)

Arguments

x

numeric, winmove. The data over which to calculate the diversity metrics

lc_class

numeric. The class values to include in the diversity metric calculation

d

numeric. If type=circle, the radius of the circle (in units of the CRS). If type=rectangle the dimension of the rectangle (one or two numbers)

type

character. The shape of the moving window

...

further arguments passed to or from other methods

Value

If class(x) == "winmove", a smoothed raster with the diversity metric calculated within the specified moving window

If class(x) == "numeric", a single value representing the diversity metric in

x

Details

Currently provided diversity metrics are Shannon diversity and Shannon evenness. Open a new issue (https://github.com/laurajanegraham/grainchanger/issues) to request additional diversity metrics.

References

McGarigal, K. and Marks, B.J., 1995. FRAGSTATS: spatial pattern analysis program for quantifying landscape structure. Gen. Tech. Rep. PNW-GTR-351. Portland, OR: US Department of Agriculture, Forest Service, Pacific Northwest Research Station. 122 p, 351.

Examples

# load required data
data(cat_ls)

# convert data to object of class winmove
cat_ls <- new("winmove", cat_ls)
#> Error in slot(value, what): no slot of name "srs" for this object of class "RasterLayer"

# calculate Shannon diversity in a rectangular window of dimension 5
d <- shdi(cat_ls, d = 5, type = "rectangle", lc_class = 1:4)
#> Error in UseMethod("shdi"): no applicable method for 'shdi' applied to an object of class "c('RasterLayer', 'Raster', 'BasicRaster')"

# convert data to object of class numeric
cat_ls <- raster::values(cat_ls)

# calculate Shannon evenness
d <- shei(cat_ls, lc_class = 1:4)