Calculate Forest Metrics by Polygon

Functional Overview

Calculate the forest metrics based on the point cloud data in the given polygon file. The forest metrics include elevation, intensity, canopy cover, Leaf Area Index and gap fraction. Read the position information of the polygon(s) stored in the input SHP file. Calculate the forest metrics and generate a result record for each polygon.

Usage

Click ALS Forest > Forest Metrics > Calculate Forest Metrics by Polygon to generate the selected forest metrics.

Parameters Settings

• Input Data: Make sure that all the input files are normalized. The input file(s) can be a single file or a file set. The file(s) to be processed must be opened in LiDAR360 before using this function.
• SHP file: The vector data that contains the polygon(s) in which the users need to generate the forest metrics. The SHP file can be added to LiDAR360 or manually input by the users.
• Height Threshold (meter) (default value is "2"): The threshold to divide the data in vertical direction. The point cloud above this height will be used to calculate the forest metrics. The default value is 2m.
• Leaf Angle Distribution (default "0.5"): A mathematical expression of leaf probability distribution in three-dimensional space, which is related to vegetation type, leaf angle, and beam direction. According to the empirical formula, the user can determine the value of leaf angle distribution according to the actual situation of the forest. Studies have shown that the elliptic distribution of leaf angle, which has a leaf angle distribution value of 0.5, may be applicable to the actual situation.
• Output Path: Path of the output file. After the output path is run, each calculation will generate a corresponding CSV file.
• Default: Restore the height threshold and leaf inclination angle distribution to the default values.

Note: Only when the point cloud data is loaded in the software can you use the Elevation Metrics function; otherwise, the message "There is no point cloud data meeting the conditions of calculation!" will pop up. If the maximum Z value of the point cloud is greater than 200 or the maximum Z minus the minimum Z is greater than 200, the data is considered to be unnormalized, and the software will pop up the prompt message shown in the figure below, click "YES", this type of data Still participating in the calculation, click "NO", this type of data will not participate in the calculation, and the user can re-select the data that meets the conditions.