Command Line Executables For Preparing LIDAR Data (2013)

LIDAR data oftentimes requires preparation before further analysis can be completed on the data. LP360 has six command line executables which can be used for preparing LIDAR data before adding it to LP360 for Windows or the LP360 for ArcGIS extension. When installed in the default folder, these preparatory

LP360 command line executables may be found in “C:\Program Files\Common Files\QCoherent” and are called:

• LDFltLine – Assign Point Source IDs (Flight line numbers)
• LDImport – Convert ASCII or MG4 data files to the LAS format
• LDMerge – Combine multiple LAS files into a single LAS file
• LDPyramid – Generate pyramid files for visualizing and processing in LP360
• LDReorder – Reorders the data spatially within the LAS file
• LDThin – Thin dataset removing every nth point

It is important to note that the type of LIDAR data itself (Mobile, Airborne or Terrestrial Scanner) may help determine which executables are needed for the preparation process. The collection criteria, such as nominal point spacing, and the desired analysis will also play a factor.

There are multiple advantages to using the LP360 command line executables, including:

1. The LD*.EXE command line executables use neither an LP360 nor an ArcGIS license and thus can be run on any machine which has the command line files installed.
2. Commands can be run on an entire folder of LAS files or specific files.
3. Commands can be batched with other LP360 command line executables.
4. Commands can be kicked off to run overnight or on a weekend.
5. Data is ready to be loaded directly into LP360 once complete.

LDPyramid is the most commonly used command line executable for preparing all three kinds of LIDAR data. It is designed to create the pyramid files that LP360 uses when displaying data. Generally the thinning factor is set to 16 as a default value, although this can be changed to be set anywhere between 2 and 99. The smaller the thinning factor, the fewer changes will occur when zooming into data within LP360. It is recommended to always pyramid data files before using them in LP360. LP360 by default will generate pyramids for files which do not have any when you first load the data into the software.