lasground
Classify points as ground or not ground
Implements a Progressive Morphological Filter for segmentation of ground points.
The function updates the field Classification of the input LAS object. The points
classified as 'ground' are assigned a value of 2 according to las specifications (See the ASPRS
documentation for the
LAS file format).
This function is an implementation of the Zhang et al. (2003) algorithm (see reference)
Usage
lasground(.las, MaxWinSize = 20, Slope = 1, InitDist = 0.5, MaxDist = 3,
CellSize = 1, ...)Arguments
- .las
a LAS object
- MaxWinSize
numeric. Maximum window size to be used in filtering ground returns (see references)
- Slope
numeric. Slope value to be used in computing the height thresholds (see references)
- InitDist
numeric. Initial height above the parameterized ground surface to be considered a ground return (see references)
- MaxDist
numeric. Maximum height above the parameterized ground surface to be considered a ground return (see references)
- CellSize
numeric. Cell size
- ...
Any additional specific parameters to be passed to the progressive morphological filter. These include: -
exponentiallogical. Default is TRUE. -basenumeric. Default is 2
Value
Nothing. The original LAS object is updated by reference. In the 'Classification' column a value of 2 denotes ground according to LAS specifications.
References
Zhang, K., Chen, S. C., Whitman, D., Shyu, M. L., Yan, J., & Zhang, C. (2003). A progressive morphological filter for removing nonground measurements from airborne LIDAR data. IEEE Transactions on Geoscience and Remote Sensing, 41(4 PART I), 872<U+2013>882. http:#doi.org/10.1109/TGRS.2003.810682
Examples
# NOT RUN {
LASfile <- system.file("extdata", "Topography.laz", package="lidR")
las = readLAS(LASfile, XYZonly = TRUE)
lasground(las, MaxWinSize = 40, Slope = 1, MaxDist = 5, InitDist = 0.01, CellSize = 7)
plot(las, color = "Classification")
# }