Alpha-shape Volume point cloud — alpha_volume

Returns the alpha shape volume measured from a tree point cloud.

Usage

alpha_volume_pc(pc, alpha = 1, plot = FALSE, plotcolor = "#fac87f")

Arguments

pc: The point cloud as a data.frame with columns X,Y,Z (e.g. output of read_tree_pc).
alpha: Numeric value (default=1) alpha for the computation of the 3D alpha-shape of the point cloud based on ashape3d.
plot: Logical (default=FALSE), indicates if the alpha-shape is plotted.
plotcolor: color for plotting 3D shape. Only relevant when plot = TRUE.

Value

The volume of the point cloud (numeric value) as the volume of the 3D alpha-shape computed from the points of point cloud. Also optionally (plot=TRUE) plots the alpha-shape and in this case returns a list with the volume of the point cloud as first element and the alphashape3d object as the second element. The 3D plot can be reconstructed using plot(output$alphashape3d).

Details

This function uses ashape3d and volume_ashape3d to calculate the volume of 3D the alpha-shape fitted to the point cloud.

Examples

if (FALSE) {
# Read tree point cloud and calculate the volume
pc_tree <- read_tree_pc(PC_path = "path/to/point_cloud.txt")
vol_tree <- alpha_volume_pc(pc = pc_tree)
# and plot the 3D alpha-shape
output <- alpha_volume_pc(pc = pc_tree, plot = TRUE)
vol_tree <- output$volume
# classify the tree point cloud and calculate the crown volume
crown_pc <- classify_crown_pc(
  pc, thresholdbranch, minheight, buttress,
  thresholdR2, thresholdbuttress,
  maxbuttressheight, FALSE
)
vol_crown <- alpha_volume_pc(pc = crown_pc$crownpoints, alpha = 2)
}