leaf_geometry: Calculates leaf orientation

In ilyamaclean/microclima: microclimate modelling with R

Calculates leaf orientation

Description

leaf_geometry is used to calculates the ratio of vertical to horizontal projections of leaf foliage.

Usage

leaf_geometry(veghgt, maxx = 8)

Arguments

veghgt	a SpatRaster object, two-dimensional array or matrix of vegetation heights (m).
maxx	a theoretical upper limit for the ratio of vertical to horizontal projections of leaf foliage, to which all values are capped.

Details

Under vegetated canopies, canopy transmission not only decreases with canopy cover but is also affected by leaf structure. At low solar angles, radiation is lower when leaves are more vertically oriented and leaf_geometry is hence used to calculate an approximate factor indicating the degree to which vegetation is vertically orientated based on the premise that shorter vegetation is more likely to have more vertically orientated leaves. If veghgt is a SpatRaster object, a SpatRaster object is returned. This function has been calibrated using data derived from a small area of Cornwall only. It is strongly recommended that locally calibrated values units of x, y and z are identical. Use terra::project() to convert the projection to a Universal Transverse Mercator type projection system.

Value

a SpatRaster object or a two-dimensional array of numeric values representing the ratio of vertical to horizontal projections of leaf foliage. The output tends towards zero as vegetation is more vertically orientated and maxx as it is more horizontally orientated.

Examples

library(terra)
x <- leaf_geometry(rast(veg_hgt))
plot(x, main = "Leaf geometry")

ilyamaclean/microclima documentation built on Sept. 5, 2024, 8:37 p.m.