| grid_density {lidR} | R Documentation |
Creates a map of the point density. If a "pulseID" attribute is found, also returns a map of the pulse density.
grid_density(las, res = 4)
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. |
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)
LAScatalogThis 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 for a LAScatalog in grid_* functions (in bold). For
more details see the LAScatalog engine documentation:
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.
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}.
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.
LASfile <- system.file("extdata", "Megaplot.laz", package="lidR")
las <- readLAS(LASfile, filter = "-inside 684800 5017800 684900 5017900")
d <- grid_density(las, 5)
plot(d)
las <- retrieve_pulses(las)
d <- grid_density(las)
plot(d)