lidR (version 1.3.0)

lasground: Classify points as ground or not ground

Description

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: - exponential logical. Default is TRUE. - base numeric. 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")
# }