epm (version 1.1.4)

betadiv_disparity: Map change in morphological disparity

Description

Change in morphological disparity is calculating across a moving window of neighboring grid cells. To implement a custom function, see customBetaDiv.

Usage

betadiv_disparity(x, radius, slow = FALSE, nThreads = 1)

Value

Returns a sf polygons object (if hex grid) or a SpatRaster object (if square grid).

Arguments

x

object of class epmGrid.

radius

Radius of the moving window in map units.

slow

if TRUE, use an alternate implementation that has a smaller memory footprint but that is likely to be much slower. Most useful for high spatial resolution.

nThreads

number of threads for parallelization

Author

Pascal Title

Details

For each gridcell neighborhood (defined by the radius), we calculate the proportion of the full disparity contained in those grid cells, and then take the standard deviation of those proportions across the gridcell neighborhood. This way, the returned values reflect how much disparity (relative to the overall total disparity) changes across a moving window.

If the R package spdep is installed, this function should run more quickly.

References

Foote M. 1993. Contributions of individual taxa to overall morphological disparity. Paleobiology. 19:403–419.

Examples

# \donttest{
tamiasEPM

tamiasEPM <- addTraits(tamiasEPM, tamiasTraits)

z <- betadiv_disparity(tamiasEPM, radius = 150000)

plot(z)

# using square grid epmGrid
tamiasEPM2 <- createEPMgrid(tamiasPolyList, resolution = 50000,
	cellType = 'square', method = 'centroid')
tamiasEPM2 <- addTraits(tamiasEPM2, tamiasTraits)
z2 <- betadiv_disparity(tamiasEPM2, radius = 150000)

terra::plot(z2, col = sf::sf.colors(100))

# }