Estimation of Forest Canopy Height Model and Leaf Area Index Using Airborne LiDAR data
2013
Hochschulschrift
Zugriff:
101
Efficiently obtaining the information in forest region such as forest structure, forest ecosystems is important for forestry management. Remote sensing has been considered as a practical technology to acquire the data of a large area. Compared with spectral images, airborne light detection and ranging (LiDAR) can provide three dimensional coordinates directly, and the penetration characteristics of LiDAR system makes the possibility of seeing through the canopy. Therefore, the structure or the terrain under the canopy can be characterized by the LiDAR point cloud data. The purpose of this study is to estimate the Canopy Height Model (CHM) and the Leave Area Index (LAI) of a dense forest area by using airborne LiDAR data. CHM is estimated by taking the difference of DSM and DEM derived from LiDAR data. Estimation of LAI is achieved based on the calculation of Laser Penetration Index (LPI). Five calculations of LPI were applied in this paper: (1.) The ratio between the number of ground points and that of all the points; (2.) the ratio between the intensities of ground points and that of all the points; (3) the ratio between the number of ground points and the number of laser beams; (4) a weighting method modified from index (1); and (5) the ratio between the area of ground points and that of all the points. The study area is in a nature broadleaf forest of south Taiwan. In this study, we use three sets of airborne LiDAR data acquired with different full waveform LiDAR systems including Leica ALS60, Riegl LMS-Q680i and Optech Pegasus HD400. All of these LiDAR systems are capable of recording full waveform data, then we can get the waveform point clouds by the echo detector to do the comparison. Our experiments results show that the accuracy of CHM by different LiDAR data is about 1.5 meter. And the fourth LPI index has the highest coefficient of determination (about 0.8) and the estimation of LAI can be improved by using the waveform points.
Titel: |
Estimation of Forest Canopy Height Model and Leaf Area Index Using Airborne LiDAR data
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Autor/in / Beteiligte Person: | Li-PingLin ; 林莉萍 |
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Veröffentlichung: | 2013 |
Medientyp: | Hochschulschrift |
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