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)
An object of class LAS or LAScatalog.
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
RasterLayer
s are written on disk when running the function with a LAScatalog
, a
virtual raster mosaic is returned (see gdalbuildvrt)
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 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.
# 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)
# }
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