VoxR (version 1.0.0)

tree_metrics: Estimates a set of morphological parameters from a tls point cloud of a tree.

Description

Estimates a set of morphological parameters from a tls point cloud of a tree.

Usage

tree_metrics(
  data,
  dbh,
  height,
  crown_diameter,
  crown_proj_area,
  volume,
  message
)

Arguments

data

a data.frame or data.table containing the x, y, z, ... coordinates of a point cloud.

dbh

numeric and optional. Estimate tree DBH ?

height

numeric and optional. Estimate tree height ?

crown_diameter

numeric and optional. Estimate tree average crown diameter ?

crown_proj_area

numeric and optional. Estimate tree crown projected area ?

volume

numeric and optional. Estimate tree volume ?

message

logical. If FALSE, messages are disabled. Default = TRUE.

Value

a list containing the estimated value for each parameter.

Details

Selecting parameters to compute

If none of dbh,height,crown_diameter, crown_proj_area and volume are passed, all parameters are computed. However, the user can select a set of parameters by declaring wich parameters should be computed (all other are not).

Parameters estimates

The tree DBH is estimated as the diameter of a circle fitted to the point cloud between 1.2m and 1.4m above the ground. The tree height is computed as the elevation difference between the lowest and the highest points of the point cloud. Two values are provided for crown parameter. First a 2D convex hull is used to identify the external points of the crown. Then, a first estimate of the crown diameter ("distant_points") is computed as the average distance of each point to the further point. A second estimate ("circle_fitting") correspond to the diameter of a circle fitted to the crown external points. The crown projected area is computed as the area of a 2D convex hull that wraps the projected crown. The volume is computed as the volume of a 3D convex hull that wraps the point cloud.

Examples

# NOT RUN {
#- import tls data
tls=data.table::fread(system.file("extdata", "Tree_t0.asc", package="VoxR"))

#- compute all metrics
VoxR::tree_metrics(tls)

#- compute DBH only
VoxR::tree_metrics(tls,dbh = TRUE)

#- compute DBH and height
VoxR::tree_metrics(tls,dbh = TRUE,height = TRUE)
# }