LAI determination in forestry ecosystem by LiDAR data analysis
LAI determination in forestry ecosystem by LiDAR data analysis
LAI determination in forestry ecosystem by LiDAR data analysis
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Data <strong>analysis</strong>• A random re-sampl<strong>in</strong>g procedure of <strong>LiDAR</strong> <strong>data</strong> to estimate different laser po<strong>in</strong>ts densitieswas performed (from a density of 2 pts/m 2 to 1 pts/100 m 2 ).R 2 1,000,890,900,850,890,790,800,840,700,710,680,700,650,730,57 0,610,600,530,500,550,490,400,410,30Constant radius (5 m)0,20Variable radius0,260,27Polynomial <strong>in</strong>terpolation0,210,100,110,002 1 0,5 0,25 0,12 0,05 0,028 0,02 0,013 0,01Po<strong>in</strong>ts density (pts/m2)The pattern of correlation coefficient(R 2 ) between measured <strong>LAI</strong> and LPIcalculated on the basis ofneighbourhood <strong>analysis</strong> performedus<strong>in</strong>g a fixed radius (5 m) is reported<strong>in</strong> blue.In this case, R 2 decreases very fast <strong>by</strong>reduc<strong>in</strong>g laser po<strong>in</strong>ts density.To have a constant number of sampl<strong>in</strong>g po<strong>in</strong>ts, a variable radius for each re-sampl<strong>in</strong>g wasused apply<strong>in</strong>g the equation:r = (150/πρπρ) ½where r is <strong>in</strong> meters, ρ is the po<strong>in</strong>ts density (pts/m 2 ) and 150 is the number of po<strong>in</strong>ts with aradius of 5 m and a po<strong>in</strong>ts density of 2 pts/m 2 .-- Introduction -- The <strong>data</strong> --Methodology - Analysis - Conclusions --