Journal of Geo-information Science >
Effects of Airborne LiDAR Point Cloud Density and Interpolation Methods on the Accuracy of DEM and Surface Roughness
Received date: 2022-07-07
Revised date: 2022-08-24
Online published: 2023-04-19
Supported by
National Natural Science Foundation of China(42271438)
Shandong Provincial Natural Science Foundation, China(ZR2020YQ26)
Shandong Provincial Natural Science Foundation, China(ZR2019MD007)
A Project of Shandong Province Higher Educational Youth Innovation Science and Technology Program(2019KJH007)
Airborne LiDAR point clouds are the main data source for obtaining high-quality Digital Elevation Model (DEM), and surface roughness, as the main derivative of DEM, plays an important role in geoscience research. However, there is no clear conclusion about the influence of the airborne LiDAR point cloud data density and interpolation methods on the accuracy of DEMs and surface roughness. Thus, this paper evaluates the performance of five classical interpolation methods including Ordinary Kriging (OK), Radial Basis Function (RBF), Triangulated Irregular Network (TIN), Natural Neighbor (NN), and Inverse Distance Weighting (IDW) for quantifying surface roughness using different LiDAR data density (90%, 70%, 50%, 30%, and 10% of the original data) in three study sites with different terrain characteristics. The results show that: (1) the accuracy of each DEM interpolation algorithm decreases with the decrease of point cloud density, and when the data amount is reduced to 30% of the original data amount, the accuracy of different algorithms is obviously different. Among them, RBF and OK have the highest accuracy, while IDW has the lowest accuracy; (2) the DEM error is positively correlated with surface roughness. With the decrease of data density, the correlation coefficients between DEM error and roughness obtained by OK, RBF, and IDW methods all decrease, and the correlation coefficients between DEM error and roughness obtained by TIN and NN decrease first and then increase at density of 30%; (3) The surface roughness error extracted from DEM based on all interpolation methods increases with the decrease of data density, and the accuracy of IDW derived roughness is the highest when the data density is 90% and 70%. When the data density is reduced by 50%, RBF can capture terrain changes more accurately.
BEI Yixuan , CHEN Chuanfa , WANG Xin , SUN Yanning , HE Qingxin , LI Kunyu . Effects of Airborne LiDAR Point Cloud Density and Interpolation Methods on the Accuracy of DEM and Surface Roughness[J]. Journal of Geo-information Science, 2023 , 25(2) : 265 -276 . DOI: 10.12082/dqxxkx.2023.220486
图1 试验区域原始DEM及山体阴影图Fig. 1 Original DEMs of the test area and shadow map of the mountain |
表1 试验数据的统计信息Tab. 1 Statistical information of the experimental data |
试验区域 | 地形特征 | 点云密度/(pts/m2) | 平均坡度/° | 平均高程/m | 高程范围/m |
---|---|---|---|---|---|
Samp1 | 覆盖高大植被的斜坡 | 1.31 | 29.85 | 340.0 | 239.6~451.4 |
Samp2 | 地形复杂的峰鞘沟谷 | 0.59 | 30.16 | 102.2 | 15.3~185.9 |
Samp3 | 陡坡 | 2.57 | 30.65 | 376.5 | 253.6~489.6 |
表2 试验数据的采集信息Tab. 2 Collection information of the datasets |
试验区域 | 位置 | 采集时间 | 扫描设备 | 飞行高度/m | 扫描角度/° | 重叠度/% |
---|---|---|---|---|---|---|
Samp1 | 加利福尼亚州 | 2017年10月 | Optech Titan | 650~1250 | ±20 | >50 |
Samp2 | 奥克兰 | 2016—2018年 | Optech Galaxy | 1975 | ±34 | 30 |
Samp3 | 俄勒冈州 | 2015年6月 | Optech Gemini | 900 | ±15 | 50 |
表3 试验区域平均点间距及插值分辨率Tab. 3 Number of point clouds and average distance between neighbor points (m) |
试验区域 | 平均点间距 | DEM分辨率 |
---|---|---|
Samp1 | 0.88 | 0.45 |
Samp2 | 1.30 | 0.65 |
Samp3 | 0.62 | 0.30 |
表4 不同数据缩减下的点云数量Tab. 4 The number of sample points after data reduction |
试验区域 | 点云数量/个 | ||||
---|---|---|---|---|---|
90% | 70% | 50% | 30% | 10% | |
Samp1 | 294 512 | 206 158 | 147 256 | 88 354 | 29 451 |
Samp2 | 132 078 | 92 455 | 66 039 | 39 623 | 13 208 |
Samp3 | 579 075 | 405 353 | 289 538 | 173 723 | 57 908 |
图4 10%数据密度条件下对Samp1插值所得山体阴影图Fig. 4 Hillshades of all the interpolation methods on Samp1 with 10% data density |
图5 10%数据密度条件下对Samp2插值所得山体阴影图Fig. 5 Hillshades of all the interpolation methods on Samp2 with 10% data density |
表5 各种算法所得地表粗糙度RMSE |
试验区域 | 数据密度/% | RMSE | ||||
---|---|---|---|---|---|---|
OK | RBF | TIN | NN | IDW | ||
Samp1 | 90 | 0.168 | 0.167 | 0.168 | 0.172 | 0.154 |
70 | 0.169 | 0.167 | 0.169 | 0.178 | 0.158 | |
50 | 0.169 | 0.169 | 0.173 | 0.189 | 0.169 | |
30 | 0.178 | 0.175 | 0.198 | 0.208 | 0.188 | |
10 | 0.197 | 0.190 | 0.258 | 0.258 | 0.221 | |
Samp2 | 90 | 0.243 | 0.241 | 0.245 | 0.247 | 0.231 |
70 | 0.245 | 0.242 | 0.246 | 0.248 | 0.237 | |
50 | 0.250 | 0.247 | 0.250 | 0.255 | 0.251 | |
30 | 0.258 | 0.254 | 0.269 | 0.311 | 0.278 | |
10 | 0.280 | 0.271 | 0.664 | 0.554 | 0.323 | |
Samp3 | 90 | 0.133 | 0.133 | 0.136 | 0.143 | 0.130 |
70 | 0.134 | 0.134 | 0.134 | 0.144 | 0.133 | |
50 | 0.136 | 0.136 | 0.138 | 0.136 | 0.137 | |
30 | 0.141 | 0.139 | 0.149 | 0.150 | 0.148 | |
10 | 0.152 | 0.148 | 0.202 | 0.211 | 0.167 |
Tab. 5 The accuracy of surface roughness obtained by various algorithms (m) |
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