Stem Curvature

Overview

This function calculates the curvature of individual tree stems. The stem shape is simplified into a B-spline curve according to canopy height, then segmented according to inflection points or specified lengths (cutting analysis). The curvature, volume, and individual segments are calculated and output. The calculation principle of curvature for a single tree segment is shown in the figure below. The curvature is the ratio of the maximum rise (h) to the DBH (d) at the top of the segment. The bottom end is the cutting position near the tree base, and the top end is the cutting position near the tree tip.

Parameter Settings

• Input Data: The input data must be normalized and segmented individual tree point cloud data. Refer to Normalization or Normalization by Ground Points for normalization methods. The input file can be a single point cloud data file or a point cloud dataset; the data must be opened in LiDAR360 software.
• Individual Tree Attribute File: The input data is the individual tree attribute file corresponding to the point cloud, supporting treedb or csv. The csv file is a comma-separated CSV table and must contain at least two fields: TreeLocationX, TreeLocationY. Refer to Individual Tree Segmentation Result File Format for details.
• Tree Trunk Category (default "23"): The category of the tree trunk contained in the point cloud. The algorithm will first extract the tree trunk according to this category.
• Height Above Ground Points (meters) (default "0.3"): Only point clouds above this height will be counted.
• Layer Height: Segment the trunk according to the layer height and simplify the trunk shape into a B-spline curve.
• Minimum Rise (meters) (default "0.008"): Rises below this value will be considered noise. This threshold is used to simplify the shape of the B-spline curve formed by the trunk.
• Segmentation Method:
  • Automatic Segmentation: Automatically segment the fitted trunk curve at inflection points.
  • Segmentation by Length: Segment the fitted trunk curve according to the specified length.

Note: After the operation, the calculated curvature (CBH), volume, and individual segment results will be added to the end column. If this column already exists, it will be overwritten.