High-Quality Contour Line Generation from LiDAR Point Clouds for the Area of Forests

A methodology for both accurate and smooth contour line generation from Light Detection 1 and Ranging (LiDAR) point clouds is proposed in this paper. In order to improve the accuracy of 2 contour lines in the area of forests, constrained triangulation networks with break lines are then 3 constructed to generate contour lines. In break line extraction, a bi-threshold method for edge line 4 detection is used to extract both complete and reliable break lines. A point clouds elevation adjustment 5 with constrain of break lines and an interpolator considering a contour interval is proposed to improve 6 the smoothness of contour lines. The proposed interpotator is also can avoid contour line intersection 7 when contour lines are interpolated. Statistical parameters and shape index are then used to evaluate 8 quantitatively the accuracy and smoothness of the resultant contour lines, which fill in the blank 9 of contour lines evaluation in theory. The experiments show that high-quality contours in terms of 10 smoothness and accuracy can be generated from LiDAR point clouds. 11