DBH minimum tree radius ratio TreeQSM — dbh_minradius_ratio

Calculates the ratio between the dbh and the minimum tree radius from a TreeQSM.

Usage

dbh_minradius_ratio_qsm(
  treedata,
  cylinder,
  pc = NA,
  buttress = FALSE,
  thresholdR2 = 0.001,
  slice_thickness = 0.06,
  thresholdbuttress = 0.001,
  maxbuttressheight = 7,
  concavity = 4,
  dtm = NA,
  r = 5
)

Arguments

treedata: Treedata field of a TreeQSM that is returned by read_tree_qsm.
cylinder: Cylinder field of a TreeQSM that is returned by read_tree_qsm.
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.
buttress: Logical (default=FALSE), indicates if the trees have buttresses. Only relevant if pc is available.
thresholdR2: Numeric value (default=0.001). Parameter of the dbh_pc function used to calculate the diameter at breast height. Only relevant if the tree point cloud is available and buttress == FALSE.
slice_thickness: Numeric value (default = 0.06). Parameter of the dbh_pc and dab_pc functions used to calculate the diameter at breast height and above buttresses. Only relevant if the tree point cloud is available.
thresholdbuttress: Numeric value (default=0.001). Parameter of the dab_pc function used to calculate the diameter above buttresses. Only relevant if the tree point cloud is available and buttress == TRUE.
maxbuttressheight: Numeric value (default=7). Parameter of the dab_pc function used to calculate the diameter at breast height. Only relevant if the tree point cloud is available and buttress == TRUE.
concavity: Numeric value (default=4) concavity for the computation of the functional diameter using a concave hull based on concaveman. only relevant when a point cloud is provided.
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.

Value

The ratio of the dbh and the minimum tree radius.

Details

This ratio is defined as "Ratio between the DBH and the minimum of the vertical bin radius estimates" (Akerblom et al., 2017 & Terryn et al., 2020). The vertical bin radius estimates are calculated with vertical_bin_radii_qsm. DBH is calculated with dbh.

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

if (FALSE) {
# Read tree qsm and calculate the dbh minimum tree radius ratio
qsm <- read_tree_qsm(QSM_path = "path/to/qsm.mat")
dmrr <- dbh_minradius_ratio_qsm(
  treedata = qsm$treedata,
  cylinder = qsm$cylinder
)
# with point cloud data
pc_tree <- read_tree_pc(PC_path = "path/to/point_cloud.txt")
dmrr <- dbh_minradius_ratio_qsm(
  treedata = qsm$treedata,
  cylinder = qsm$cylinder, pc = pc_tree
)
# for a buttressed tree
dmrr <- dbh_minradius_ratio_qsm(
  treedata = qsm$treedata,
  cylinder = qsm$cylinder, pc = pc_tree,
  buttress = TRUE
)
}