| gap_fraction_profile {lidR} | R Documentation |
Computes the gap fraction profile using the method of Bouvier et al. (see reference)
gap_fraction_profile(z, dz = 1, z0 = 2)
z |
vector of positive z coordinates |
dz |
numeric. The thickness of the layers used (height bin) |
z0 |
numeric. The bottom limit of the profile |
The function assesses the number of laser points that actually reached the layer z+dz and those that passed through the layer [z, z+dz]. By definition the layer 0 will always return 0 because no returns pass through the ground. Therefore, the layer 0 is removed from the returned results.
A data.frame containing the bin elevations (z) and the gap fraction for each bin (gf)
Bouvier, M., Durrieu, S., Fournier, R. a, & Renaud, J. (2015). Generalizing predictive models of forest inventory attributes using an area-based approach with airborne las data. Remote Sensing of Environment, 156, 322-334. http://doi.org/10.1016/j.rse.2014.10.004
z <- c(rnorm(1e4, 25, 6), rgamma(1e3, 1, 8)*6, rgamma(5e2, 5,5)*10) z <- z[z<45 & z>0] hist(z, n=50) gapFraction = gap_fraction_profile(z) plot(gapFraction, type="l", xlab="Elevation", ylab="Gap fraction")