R: Create an object of class LAScatalog

readLAScatalog {lidR} | R Documentation

## Create an object of class LAScatalog

### Description

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.

### Usage

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

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

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

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

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

    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 catalog_options_tools.
`...` | Extra parameters to list.files. Typically `recursive = TRUE`.

### Value

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/a/folder/of/las/files")

    # 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.
    opt_output_files(ctg) <- "/path/to/folder/templated_filename_{XBOTTOM}_{ID}"

    # More details in the documentation
    help("LAScatalog-class", "lidR")
    help("catalog_options_tools", "lidR")

    ## End(Not run)

[Package lidR version 3.2.2 Index]