Crown start height TreeQSM

Calculates the crown start height from a TreeQSM.

Usage

crown_start_height_qsm(treedata, cylinder, pc = NA, 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.

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 crown start height.

Details

The crown start height is defined as "The height of the first stem branch in the tree crown relative to the tree height" (Akerblom et al., 2017 & Terryn et al., 2020). The tree height is calculated with tree_height. Crown cylinders are determined with crownset_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 crown start height
qsm <- read_tree_qsm(QSM_path = "path/to/qsm.mat")
csh <- crown_start_height_qsm(
  treedata = qsm$treedata,
  cylinder = qsm$cylinder
)
# with point cloud data
pc_tree <- read_tree_pc(PC_path = "path/to/point_cloud.txt")
csh <- crown_start_height_qsm(
  treedata = qsm$treedata,
  cylinder = qsm$cylinder, pc = pc_tree
)
}