lidR (version 1.6.1)

lasadddata: Add data into a las object

Description

A LAS object represents a .las file in R. According to the LAS specifications a las file contains a core of defined variables such as XYZ coordinates, intensity, return number, and so on for each point. It is possible to add supplementary data. The functions lasadd* enable the user to add new data (see details)

Usage

lasadddata(las, x, name)
lasaddextrabytes(las, x, name, desc)
lasaddextrabytes_manual(las, x, name, desc, type, offset = NULL,
  scale = NULL, NA_value = NULL)

Arguments

las

an object of class LAS

x

a vector that need to be added in the LAS object. If missing, the colum 'name' of the existing LAS object will be used.

name

character. The name of the extrabytes attributes to add in the file.

desc

character. A short description of the extrabytes attributes to add in the file.

type

character. The data type of the extra bytes attribute. Can be "uchar", "char", "ushort", "short", "uint", "int", "uint64", "int64", "float", "double".

scale, offset

numeric. The scale and offset of the data. NULL if not relevant.

NA_value

numeric or integer. NA is not a valid value in a las file. At writing time it will be replaced by this value that will be considered as NA. NULL if not relevant.

Value

Nothing (NULL). The LAS object is updated in place by reference to avoid copies.

Details

lasadddata simply adds a new column in the data but does not update the header. Thus the LAS object is not strictly valid. These data will be usable at the R level but will not be written in a las file with writeLAS. lasaddextrabyte does the same as lasadddata but updates automatically the header of the LAS object. Thus, the LAS object is valid and the new data is considered as "extra bytes". This new data will be written in a las file with writeLAS lasaddextrabyte_manual allows the user to manually write all the extra bytes information. This function is reserved for experienced users with a good knowledge of the LAS specifications. The function does not perform tests to check the validity of the information.

Examples

# NOT RUN {
LASfile <- system.file("extdata", "example.laz", package="rlas")
las = readLAS(LASfile)

print(las)
print(las@header)

x= 1:30

lasadddata(las, x, "mydata")
print(las) # The las object has a new field called "mydata"
print(las@header) # But the header has not been updated. This new data will not be written

lasaddextrabytes(las, x, "mydata2", "A new data")
print(las) # The las object has a new field called "mydata2"
print(las@header) # The header has not been updated. This new data will be written

# optionally if the data is already in the LAS object you can update the header skipping the
# parameter x
lasaddextrabytes(las, name ="mydata", desc = "Amplitude")
print(las@header)
# }