grid_density

0th

Percentile

Map the pulse or point density

Creates a map of the point density. If a "pulseID" attribute is found, also returns a map of the pulse density.

Usage
grid_density(las, res = 4)
Arguments
las

An object of class LAS or LAScatalog.

res

numeric. The size of a grid cell in LiDAR data coordinates units. Default is 4 = 16 square meters.

Value

A RasterLayer or a RasterBrick containing a numeric value in each cell. If the RasterLayers are written on disk when running the function with a LAScatalog, a virtual raster mosaic is returned (see gdalbuildvrt)

Working with a LAScatalog

This section appears in each function that supports a LAScatalog as input.

In lidR when the input of a function is a LAScatalog the function uses the LAScatalog processing engine. The user can modify the engine options using the available options. A careful reading of the engine documentation is recommended before processing LAScatalogs. Each lidR function should come with a section that documents the supported engine options.

The LAScatalog engine supports .lax files that significantly improve the computation speed of spatial queries using a spatial index. Users should really take advantage a .lax files, but this is not mandatory.

Supported processing options

Supported processing options for a LAScatalog in grid_* functions (in bold). For more details see the LAScatalog engine documentation:

  • tiling_size: How much data is loaded at once. The tiling size may be slightly modified internally to ensure a strict continuous wall-to-wall output even when tiling size is equal to 0 (processing by file).

  • buffer: This function guarantees a strict continuous wall-to-wall output. The buffer option is not considered.

  • alignment: Align the processed clusters. The alignment may be slightly modified.

  • chunk size: How much data is loaded at once. The chunk size may be slightly modified internally to ensure a strict continuous wall-to-wall output even when chunk size is equal to 0 (processing by file).

  • chunk buffer: This function guarantees a strict continuous wall-to-wall output. The buffer option is not considered.

  • chunk alignment: Align the processed chunks. The alignment may be slightly modified internally to ensure a strict continuous wall-to-wall output.

  • cores: How many cores are used.

  • progress: Displays a progress estimate.

  • output_files: Return the output in R or write each cluster's output in a file. Supported templates are XLEFT, XRIGHT, YBOTTOM, YTOP, XCENTER, YCENTER ID and, if chunk size is equal to 0 (processing by file), ORIGINALFILENAME.

  • laz_compression: is not supported because this function will never write las/laz files.

  • select: The grid_* functions usually 'know' what should be loaded and this option is not considered. In grid_metrics this option is respected.

  • filter: Read only the points of interest.

Aliases
  • grid_density
Examples
# NOT RUN {
LASfile <- system.file("extdata", "Megaplot.laz", package="lidR")
lidar = readLAS(LASfile)

d = grid_density(lidar, 5)
plot(d)
d = grid_density(lidar, 10)
plot(d)
# }
Documentation reproduced from package lidR, version 2.0.0, License: GPL-3

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