Read data from a .las or .laz file
Reads data from .las or .laz files according to LAS specifications and returns
a data.table labeled according to LAS specifications. See the ASPRS documentation for the
LAS file format.
The optional parameters enable the user to save memory by choosing to load only the
fields they need. Moreover, the function provides a streaming filter to load only the points of
interest into the memory and hence avoids allocating any superfluous memory.
read.las(files, select = "*", filter = "", transform = "")
files |
array of characters |
select |
character. select only columns of interest to save memory (see details) |
filter |
character. streaming filters - filter data while reading the file (see details) |
transform |
character. streaming transformation - transform data while reading the file (see details) |
Select: the 'select' argument specifies the data that will actually be loaded. For example,
'xyzia' means that the x, y, and z coordinates, the intensity and the scan angle will be loaded.
The supported entries are t - gpstime, a - scan angle, i - intensity, n - number of returns,
r - return number, c - classification, s - synthetic flag, k - keypoint flag, w - withheld flag,
o - overlap flag (format 6+) u - user data, p - point source ID, e - edge of flight line flag,
d - direction of scan flag, R - red channel of RGB color, G - green channel of RGB color,
B - blue channel of RGB color, N - near-infrared channel. C - scanner channel (format 6+).
Also numbers from 1 to 9 for the extra bytes data numbers 1 to 9. 0 enables all extra bytes to be
loaded and '*' is the wildcard that enables everything to be loaded from the LAS file.
Note that x, y, z are implicit and always loaded. 'xyzia' is equivalent to 'ia'.
Filter: the 'filter' argument allows filtering of the point cloud while reading files.
rlas relies on the well-known LASlib library written by Martin Isenburg
to read the binary files. Thus the package inherits the filter commands available in
LAStools. To use these filters the user can pass the
common commands from LAStools into the parameter 'filter'. Type read.las(filter = "-help")
to display the LASlib documentation and the available filters.
Transform: the 'transform' argument allows transformation of the point cloud while reading files.
rlas relies on the well-known LASlib library written by Martin Isenburg
to read the binary files. Thus the package inherits the tranform commands available in
LAStools. To use these transformations the user can pass the
common commands from LAStools into the parameter 'transform'. Type read.las(transform = "-help")
to display the LASlib documentation and the available transformations
A data.table
lasfile <- system.file("extdata", "example.las", package="rlas")
lasdata <- read.las(lasfile)
lasdata <- read.las(lasfile, filter = "-keep_first")
lasdata <- read.las(lasfile, filter = "-drop_intensity_below 80")
lasdata <- read.las(lasfile, select = "xyzia")Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.