The Effect of LiDAR Sampling Density on DTM Accuracy for Areas with Heavy Forest Cover
Laser scanning via LiDAR is a powerful technique for collecting data necessary for Digital Terrain Model (DTM) generation, even in densely forested areas. LiDAR observations located at the ground level can be separated from the initial point cloud and used as input for the generation of a Digital Te...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-02-01
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| Series: | Forests |
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| Online Access: | https://www.mdpi.com/1999-4907/12/3/265 |
| _version_ | 1797395244932661248 |
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| author | Mihnea Cățeanu Arcadie Ciubotaru |
| author_facet | Mihnea Cățeanu Arcadie Ciubotaru |
| author_sort | Mihnea Cățeanu |
| collection | DOAJ |
| description | Laser scanning via LiDAR is a powerful technique for collecting data necessary for Digital Terrain Model (DTM) generation, even in densely forested areas. LiDAR observations located at the ground level can be separated from the initial point cloud and used as input for the generation of a Digital Terrain Model (DTM) via interpolation. This paper proposes a quantitative analysis of the accuracy of DTMs (and derived slope maps) obtained from LiDAR data and is focused on conditions common to most forestry activities (rough, steep terrain with forest cover). Three interpolation algorithms were tested: Inverse Distance Weighted (IDW), Natural Neighbour (NN) and Thin-Plate Spline (TPS). Research was mainly focused on the issue of point data density. To analyze its impact on the quality of ground surface modelling, the density of the filtered data set was artificially lowered (from 0.89 to 0.09 points/m<sup>2</sup>) by randomly removing point observations in 10% increments. This provides a comprehensive method of evaluating the impact of LiDAR ground point density on DTM accuracy. While the reduction of point density leads to a less accurate DTM in all cases (as expected), the exact pattern varies by algorithm. The accuracy of the LiDAR-derived DTMs is relatively good even when LiDAR sampling density is reduced to 0.40–0.50 points/m<sup>2</sup> (50–60 % of the initial point density), as long as a suitable interpolation algorithm is used (as IDW proved to be less resilient to density reductions below approximately 0.60 points/m<sup>2</sup>). In the case of slope estimation, the pattern is relatively similar, except the difference in accuracy between IDW and the other two algorithms is even more pronounced than in the case of DTM accuracy. Based on this research, we conclude that LiDAR is an adequate method for collecting morphological data necessary for modelling the ground surface, even when the sampling density is significantly reduced. |
| first_indexed | 2024-03-09T00:31:38Z |
| format | Article |
| id | doaj.art-9488cc89f3124ee7adebc191d77b9451 |
| institution | Directory Open Access Journal |
| issn | 1999-4907 |
| language | English |
| last_indexed | 2024-03-09T00:31:38Z |
| publishDate | 2021-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Forests |
| spelling | doaj.art-9488cc89f3124ee7adebc191d77b94512023-12-11T18:28:53ZengMDPI AGForests1999-49072021-02-0112326510.3390/f12030265The Effect of LiDAR Sampling Density on DTM Accuracy for Areas with Heavy Forest CoverMihnea Cățeanu0Arcadie Ciubotaru1Department of Forest Engineering, Forest Management Planning and Terrestrial Measurements, Faculty of Silviculture and Forest Engineering, Transilvania University of Brașov, Șirul Beethoven 1, 500123 Brașov, RomaniaDepartment of Forest Engineering, Forest Management Planning and Terrestrial Measurements, Faculty of Silviculture and Forest Engineering, Transilvania University of Brașov, Șirul Beethoven 1, 500123 Brașov, RomaniaLaser scanning via LiDAR is a powerful technique for collecting data necessary for Digital Terrain Model (DTM) generation, even in densely forested areas. LiDAR observations located at the ground level can be separated from the initial point cloud and used as input for the generation of a Digital Terrain Model (DTM) via interpolation. This paper proposes a quantitative analysis of the accuracy of DTMs (and derived slope maps) obtained from LiDAR data and is focused on conditions common to most forestry activities (rough, steep terrain with forest cover). Three interpolation algorithms were tested: Inverse Distance Weighted (IDW), Natural Neighbour (NN) and Thin-Plate Spline (TPS). Research was mainly focused on the issue of point data density. To analyze its impact on the quality of ground surface modelling, the density of the filtered data set was artificially lowered (from 0.89 to 0.09 points/m<sup>2</sup>) by randomly removing point observations in 10% increments. This provides a comprehensive method of evaluating the impact of LiDAR ground point density on DTM accuracy. While the reduction of point density leads to a less accurate DTM in all cases (as expected), the exact pattern varies by algorithm. The accuracy of the LiDAR-derived DTMs is relatively good even when LiDAR sampling density is reduced to 0.40–0.50 points/m<sup>2</sup> (50–60 % of the initial point density), as long as a suitable interpolation algorithm is used (as IDW proved to be less resilient to density reductions below approximately 0.60 points/m<sup>2</sup>). In the case of slope estimation, the pattern is relatively similar, except the difference in accuracy between IDW and the other two algorithms is even more pronounced than in the case of DTM accuracy. Based on this research, we conclude that LiDAR is an adequate method for collecting morphological data necessary for modelling the ground surface, even when the sampling density is significantly reduced.https://www.mdpi.com/1999-4907/12/3/265ground surface modellingDTMLiDARAirborne Laser Scanning |
| spellingShingle | Mihnea Cățeanu Arcadie Ciubotaru The Effect of LiDAR Sampling Density on DTM Accuracy for Areas with Heavy Forest Cover Forests ground surface modelling DTM LiDAR Airborne Laser Scanning |
| title | The Effect of LiDAR Sampling Density on DTM Accuracy for Areas with Heavy Forest Cover |
| title_full | The Effect of LiDAR Sampling Density on DTM Accuracy for Areas with Heavy Forest Cover |
| title_fullStr | The Effect of LiDAR Sampling Density on DTM Accuracy for Areas with Heavy Forest Cover |
| title_full_unstemmed | The Effect of LiDAR Sampling Density on DTM Accuracy for Areas with Heavy Forest Cover |
| title_short | The Effect of LiDAR Sampling Density on DTM Accuracy for Areas with Heavy Forest Cover |
| title_sort | effect of lidar sampling density on dtm accuracy for areas with heavy forest cover |
| topic | ground surface modelling DTM LiDAR Airborne Laser Scanning |
| url | https://www.mdpi.com/1999-4907/12/3/265 |
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