stem_branch_radius_qsm: Stem branch radius TreeQSM

In lmterryn/ITSMe: Individual Tree Structural Metrics

Stem branch radius TreeQSM

Description

Calculates the stem branch radius from a TreeQSM.

Usage

stem_branch_radius_qsm(
  cylinder,
  treedata,
  normalisation = "treeheight",
  pc = NA,
  dtm = NA,
  r = 5
)

Arguments

cylinder	Cylinder field of a TreeQSM that is returned by read_tree_qsm.
treedata	Treedata field of a TreeQSM that is returned by read_tree_qsm.
normalisation	Can be either "treeheight" or "parentcylinder". In case of "treeheight" the mean radius of the 10 biggest branches is divided by the tree height (Terryn et al., 2020). In case of "parentcylinder" the mean is taken of the ratios of the radius of the 10 biggest branches and the radius of their parent cylinders (Akerblom et al., 2017). When something different than "treeheight" or "parentcylinder" is given, no normalisation is done. Default is no normalisation.
pc	The tree point cloud as a data.frame with columns X,Y,Z. Output of read_tree_pc. Default is NA and indicates no tree point cloud is available. Only relevant if normalisation equals "treeheight".
dtm	The digital terrain model as a data.frame with columns X,Y,Z (default = NA). If the digital terrain model is in the same format as a point cloud it can also be read with read_tree_pc. only relevant when a point cloud is provided.
r	Numeric value (default=5) r which determines the range taken for the dtm. Should be at least the resolution of the dtm. Only relevant when a dtm is provided.

Details

The stem branch radius is defined as "Mean of the 10 largest 1st order branches measured at the base. Can be normalised by the tree height or the the stem radius at respective height" (Akerblom et al., 2017 & Terryn et al., 2020). Tree height is calculated with tree_height.

Value

The stem branch radius. Unitless with normalisation, in meters without normalisation. NaN when there are no stem branches.

References

Akerblom, M., Raumonen, P., Makipaa, R., & Kaasalainen, M. (2017). Automatic tree species recognition with quantitative structure models. Remote Sensing of Environment, 191, 1-12.

Terryn, L., Calders, K., Disney, M., Origo, N., Malhi, Y., Newnham, G., ... & Verbeeck, H. (2020). Tree species classification using structural features derived from terrestrial laser scanning. ISPRS Journal of Photogrammetry and Remote Sensing, 168, 170-181.

Examples

## Not run: 
# Read tree qsm and calculate the stem branch radius
# from Akerblom et al. (2017)
qsm <- read_tree_qsm(QSM_path = "path/to/qsm.mat")
sbr <- stem_branch_radius_qsm(
  cylinder = qsm$cylinder,
  treedata = qsm$treedata,
  normalisation = "parentcyl"
)
# from Terryn et al. (2020)
sbr <- stem_branch_radius_qsm(
  cylinder = qsm$cylinder,
  treedata = qsm$treedata,
  normalisation = "treeheight"
)
# with point cloud data
pc_tree <- read_tree_pc(PC_path = "path/to/point_cloud.txt")
sbr <- stem_branch_radius_qsm(
  cylinder = qsm$cylinder,
  treedata = qsm$treedata,
  normalisation = "treeheight",
  pc = pc_tree
)

## End(Not run)

lmterryn/ITSMe documentation built on Feb. 4, 2025, 2:21 a.m.