Skip to contents

DBH-tree volume ratio TreeQSM

Source: R/metrics_Terryn_2020.R
dbh_volume_ratio_qsm.Rd

Calculates DBH-tree volume ratio from a TreeQSM.

Usage

dbh_volume_ratio_qsm(
  treedata,
  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.

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

DBH divided by the tree volume (trunk plus branches) in meters-2.

Details

DBH and tree volume are calculated with dbh and tree_volume_qsm.

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 volume ratio
qsm <- read_tree_qsm(QSM_path = "path/to/qsm.mat")
dvr <- dbh_volume_ratio_qsm(treedata = qsm$treedata)
# with point cloud data
pc_tree <- read_tree_pc("path/to/point_cloud.txt")
dvr <- dbh_volume_ratio_qsm(treedata = qsm$treedata, pc = pc_tree)
# for buttressed trees
dvr <- dbh_volume_ratio_qsm(
  treedata = qsm$treedata, pc = pc_tree,
  buttress = TRUE
)
}