Calculate Forest Metrics by Polygon

Summary

Calculate the forest metrics based on the point cloud data in the given polygon file. The forest metrics include elevation, intensity, canopy cover, LAI, and gap fraction.

Read the position information of the polygon(s) stored in the input SHP file. Calculate the forest metrics and gerenate a result record for each polygon.

Usage

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

Calculate Forest Metrics by Polygon

Settings

  • Input: 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 into 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 2.
  • Leaf Angle Distribution (default value is "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. A corresponding raster file (tif format) or CSV file will be generated for each input point cloud data, which can be used in the regression analysis.
  • DefaultValue: Restore the default parameters.

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 m or the maximum Z minus the minimum Z is greater than 200 m, the data is not considered to have been normalized, and the prompt information shown in the figure below will pop up. Click “YES” to keep using this type of data in the operation; otherwise, click "NO" and reselect the input data file.

Calculate Forest Metrics by Polygon

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