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Table 1 List of the 27 features derived from the ALS metrics extracted for each segment

From: Mapping tree canopies in urban environments using airborne laser scanning (ALS): a Vancouver case study

Feature name Description
Normalized average height Average height of all returns above 2 m, normalized by the 99th percentile of height.
Normalized standard deviation of height Standard deviation of height of all returns above 2 m, normalized by the 99th percentile of height.
Normalized average square height Average of the square of the height of all returns above 2 m, normalized by the 99th percentile of height.
Skewness of height Skewness of the height of all returns above 2 m.
Kurtosis of height Kurtosis of the height of all returns above 2 m.
Canopy cover from first returns Fraction of first returns above the 2 m threshold (number of first returns above 2 m divided by the total number of first returns)
Canopy cover from all returns Fraction of all returns above the 2 m threshold (number of all returns above 2 m divided by the total number of all returns)
Normalized percentiles of height: p = 10, 20, 30, 40, 50, 60, 70, 80, 90, 95 Percentiles of height (height below which p % of points lay), normalized by the 99th percentile of height.
Bicentiles of height: b = 10, 20, 30, 40, 50, 60, 70, 80, 90, 95 Percentage of the points whose height is below b % of the 99th percentile of height.