R: Retrieve individual pulses, flightlines or scanlines

retrieve_pulses {lidR} | R Documentation

## Retrieve individual pulses, flightlines or scanlines

### Description

Retrieve each individual pulse, individual flightline or individual scanline and assigns a number to each point. The LAS object must be properly populated according to LAS specifications otherwise users could find unexpected outputs.

### Usage

    retrieve_pulses(las)

    retrieve_flightlines(las, dt = 30)

    retrieve_scanlines(las)

### Arguments

`las` | A LAS object
`dt` | numeric. The threshold time-lag used to retrieve flightlines

### Details

`retrieve_pulses`

  Retrieves each individual pulse. It uses GPS time. An attribute `pulseID` is added in the `LAS` object

`retrieve_scanlines`

  Retrieves each individual scanline. When data are sampled according to a saw-tooth pattern (oscillating mirror), a scanline is one line, or row of data. The function relies on the GPS field time to order the data. Then, the `ScanDirectionFlag` attribute is used to retrieve each scanline. An attribute `scanlineID` is added in the `LAS` object

`retrieve_flightlines`

  Retrieves each individual flightline. It uses GPS time. In a continuous dataset, once points are ordered by GPS time, the time between two consecutive points does not exceed a few milliseconds. If the time between two consecutive points is too long it means that the second point is from a different flightline. The default threshold is 30 seconds. An attribute `flightlineID` is added in the `LAS` object.

### Value

An object of class `LAS`

### Examples

    LASfile <- system.file("extdata", "Megaplot.laz", package="lidR")
    las <- readLAS(LASfile)

    las <- retrieve_pulses(las)
    las

    las <- retrieve_flightlines(las)
    #plot(las, color = "flightlineID")

[Package lidR version 3.2.2 Index]