dsm_point2raster: Digital Surface Model Algorithm

In lidR: Airborne LiDAR Data Manipulation and Visualization for Forestry Applications

Digital Surface Model Algorithm

Description

This function is made to be used in rasterize_canopy. It implements an algorithm for digital surface model computation based on a points-to-raster method: for each pixel of the output raster the function attributes the height of the highest point found. The subcircle tweak replaces each point with 8 points around the original one. This allows for virtual 'emulation' of the fact that a lidar point is not a point as such, but more realistically a disc. This tweak densifies the point cloud and the resulting canopy model is smoother and contains fewer 'pits' and empty pixels.

Usage

p2r(subcircle = 0, na.fill = NULL)

Arguments

subcircle	numeric. Radius of the circles. To obtain fewer empty pixels the algorithm can replace each return with a circle composed of 8 points (see details).
na.fill	function. A function that implements an algorithm to compute spatial interpolation to fill the empty pixel often left by points-to-raster methods. lidR has knnidw, tin, and kriging (see also rasterize_terrain for more details).

See Also

Other digital surface model algorithms: dsm_pitfree, dsm_tin

Examples

LASfile <- system.file("extdata", "MixedConifer.laz", package="lidR")
las <- readLAS(LASfile)
col <- height.colors(50)

# Points-to-raster algorithm with a resolution of 1 meter
chm <- rasterize_canopy(las, res = 1, p2r())
plot(chm, col = col)

# Points-to-raster algorithm with a resolution of 0.5 meters replacing each
# point by a 20 cm radius circle of 8 points
chm <- rasterize_canopy(las, res = 0.5, p2r(0.2))
plot(chm, col = col)

## Not run: 
chm <- rasterize_canopy(las, res = 0.5, p2r(0.2, na.fill = tin()))
plot(chm, col = col)

## End(Not run)

lidR documentation built on Sept. 8, 2023, 5:10 p.m.