readLAScatalog function

Create an object of class LAScatalog

Create an object of class LAScatalog from a folder or a collection of filenames. A LAScatalog is a representation of a collection of las/laz files. A computer cannot load all the data at once. A LAScatalog

is a simple way to manage all the files sequentially. Most functions from lidR can be used seamlessly with a LAScatalog using the internal LAScatalog processing engine. To take advantage of the LAScatalog

processing engine the user must first adjust some processing options using the appropriate functions . Careful reading of the LAScatalog class documentation is required to use the LAScatalog class correctly.

readLAScatalog is the original function and always works. Using one of the read*LAScatalog functions adds information to the returned object to register a point-cloud type. Registering the correct point type may improve the performance of some functions by enabling users to select an appropriate spatial index. See spatial indexing . Notice that by legacy and for backwards-compatibility reasons readLAScatalog() and readALSLAScatalog() are equivalent because lidR was originally designed for ALS and thus the original function readLAScatalog() was (supposedly) used for ALS.

readLAScatalog(
  folder,
  progress = TRUE,
  select = "*",
  filter = "",
  chunk_size = 0,
  chunk_buffer = 30,
  ...
)

readALSLAScatalog(folder, ...)

readTLSLAScatalog(folder, ...)

readUAVLAScatalog(folder, ...)

readDAPLAScatalog(folder, ...)

catalog(folder, ...)

Arguments

• folder: string. The path of a folder containing a set of las/laz files. Can also be a vector of file paths.
• progress, select, filter, chunk_size, chunk_buffer: Easily accessible processing options tuning. See LAScatalog-class and engine_options .
• ...: Extra parameters to list.files . Typically recursive = TRUE. Propagates also to readLAScatalog

Returns

A LAScatalog object

Examples

# A single file LAScatalog using data provided with the package
LASfile <- system.file("extdata", "Megaplot.laz", package="lidR")
ctg = readLAScatalog(LASfile)
plot(ctg)

## Not run:

ctg <- readLAScatalog("</path/to/folder/of/las/>")

# Internal engine will sequentially process chunks of size 500 x 500 m
opt_chunk_size(ctg) <- 500

# Internal engine will align the 500 x 500 m chunks on x = 250 and y = 300
opt_alignment(ctg) <- c(250, 300)

# Internal engine will not display a progress estimation
opt_progress(ctg) <- FALSE

# Internal engine will not return results into R.
# Instead it will write results in files.
# Files will be named e.g.
# filename_256000_1.ext
# filename_257000_2.ext
# filename_258000_3.ext
# ...
opt_output_files(ctg) <- "/path/filename_{XBOTTOM}_{ID}"

# More details in the documentation
help("LAScatalog-class", "lidR")
help("engine_options", "lidR")
## End(Not run)