txt2las

Author:Martin Isenburg
Contact:isenburg@cs.unc.edu

txt2las converts LIDAR data from a standard ASCII format into the more efficient binary LAS representation.

Usage

$ txt2las -i lidar.taxyz -o lidar.las -parse ssxyz

converts ASCII file and uses the 3rd, 4th, and 5th entry of each line as the x, y, and z coordinate of each point.

$ txt2las -i lidar.txt.gz -o lidar.las -parse txyzsa

converts a gzipped ASCII file and uses the 1st entry of each line as the gps time, the 3rd, 4th, and 5th entry as the x, y, and z coordinate of each point, and the 6th entry as the scan angle

Help

C:\lastools\bin>txt2las -h
usage:
txt2las -parse tsxyz lidar.txt
txt2las -parse txyzar lidar.txt.gz lidar.laz
txt2las -parse xyz -scale 0.02 -i lidar.txt -o lidar.laz
txt2las -parse xyzsst -verbose -scale 0.05 lidar.txt
txt2las -parse xsysz -xyz_scale 0.02 0.02 0.01 lidar.txt
txt2las -h

Parsing Flags

The ‘-parse tsxyz’ flag specifies how to interpret each line of the ASCII file. For example, ‘tsxyzssa’ means that the first number is the gpstime, the next number should be skipped, the next three numbers are the x, y, and z coordinate, the next two should be skipped, and the next number is the scan angle.

The other supported entries are:
  • i - intensity
  • n - number of returns of given pulse
  • r - number of return
  • c - classification
  • u - user data
  • p - point source ID
  • e - edge of flight line flag
  • d - direction of scan flag.

Scale

The ‘-scale 0.02’ flag specifies the quantization. The default value of 0.01 means that the smallest increment two between coordinates is 0.01. If measurements are in meters this corresponds to centimeter accuracy, which is commonly considered sufficient for LIDAR data.

Other parameters

Other parameters such as ‘-xyz_offset 500000 2000000 0’ or ‘-xyz_scale 0.02 0.02 0.01’ or ‘-file_creation 67 2003’ or ‘-system_identifier “Airborne One Leica 50,000 Hz”’ or ‘-generating_software “TerraScan”’ are available too.