LAStools: converting, viewing, and compressing LIDAR data in LAS format

Martin Isenburg          Jonathan Shewchuk

abstract:
The program txt2las.exe converts LIDAR data from standard ASCII in various formattings to binary LAS format (version 1.2). The corresponding las2txt.exe turns binary LAS into human-readable and easy-to-parse textual representations. The tool lasinfo.exe prints out a quick overview of the contents of a LAS file, las2shp.exe turns binary LAS into ESRI's Shapefile format, shp2las.exe turns an ESRI's Shapefile into binary LAS, lasmerge.exe can merge several LAS files into one, las2las.exe allows extracting only last returns, only points within a bounding box, etc., lasthin.exe implements a simple point thinning algorithm, las2tin.exe triangulates the points of a LAS file into a TIN, las2dem.exe rasterizes them into a DEM, las2iso.exe extracts, optionally simplified, elevation contours, and lasboundary.exe computes a boundary polygon (i.e. a concave hull of the points). The little OpenGL viewer lasview.exe visualizes the contents of a LAS file and can also compute a TIN. It needs the GLUT32.DLL. All these programs are command line tools and their source code (with Makefile) is available. To read gzipped inputs they need gzip.exe in the path.
We provide two simple C++ classes LASreader and LASwriter that implement reading and writing of LIDAR points from and to the binary LAS format 1.0/1.1/1.2 (as described in the April 2008 specification) that are included in the lastools.zip distribution. If you find this software useful, if you find bugs, or if you have additions or suggestions to our code, please let us know.
We also provide a sophisticated LIDAR compressor laszip.exe for lossless encoding and decoding of LIDAR data stored in binary LAS format (versions 1.0/1.1/1.2). The compressed files are only 10 percent of the original file size: compare this file before (54 MB) and after (5 MB) compression. All lastools can read and write the compressed format directly (i.e. without having to first fully decompress the file). There is also a programming API so your own programs can read and write from and to our compressed format.

If you work with LAS or LIDAR you may also be interested in Visualizing LIDAR in Google Earth. There you find tools that would be called lasDEM.exe and lasTIN.exe and lasContour.exe if they were listed here. They turn lidar points into DEMs, TINs, or Contours.

download: (updated on January 28th, 2010)

  • executables, API, and source code: lastools.zip
  • txt2las.exe and txt2las_README.txt
  • las2txt.exe and las2txt_README.txt
  • lasinfo.exe and lasinfo_README.txt
  • las2shp.exe and las2shp_README.txt
  • shp2las.exe and shp2las_README.txt
  • las2tin.exe and las2tin_README.txt
  • las2dem.exe and las2dem_README.txt
  • las2iso.exe and las2iso_README.txt
  • lasboundary.exe and lasboundary_README.txt
  • lasmerge.exe and lasmerge_README.txt
  • las2las.exe and las2las_README.txt
  • lasthin.exe and lasthin_README.txt
  • lasview.exe and lasview_README.txt and GLUT32.DLL
  • laszip.exe and laszip_README.txt
  • gzip.exe needs to be in the path for reading gzipped input
  • example LIDAR data (sample files) in LAS format:

  • example data in LAS format 1.2: xyzrgb_manuscript.las
  • from qcoherent.com: LP360_Sample_Data.rar
  • from appliedimagery.com: Serpent_Mound_LAS_Data.las
  • lidar data of gilmer county
  • the USGS server's LAS data for the mississippi area
  • from capcog.org: Sample_LiDAR_LAS_File.zip
  • from liblas.org: samples/
  • related publications:

  • [ilsst-tin2dem-06.pdf] Martin Isenburg, Yuanxin Liu, Jonathan Shewchuk, Jack Snoeyink, Tim Thirion, Generating Raster DEM from Mass Points via TIN Streaming, GIScience'06 Conference Proceedings, pages 186-198, September 2006.
  • [ilss-scdt-06.pdf] Martin Isenburg, Yuanxin Liu, Jonathan Shewchuk, Jack Snoeyink, Streaming Computation of Delaunay Triangulations, Proceedings of SIGGRAPH'06, pages 1049-1056, July 2006.
  • [ilss-lidar2iso-06.pdf] Martin Isenburg, Yuanxin Liu, Jack Snoeyink, Streaming Extraction of Elevation Contours from LIDAR points, draft, april 2006.
  • related downloads:

  • slides: tin2dem.ppt (+ vids + DivX codec for vids)
  • streaming delaunay demo: sd_demo.zip (11 MB)
  • lidar points to elevation contours demo: lidar2iso_demo.zip (47 MB)
  • If you are interested in stream processing of terrain data let us know! Source code, programming APIs, and help for building your own stream processing modules is available on request.

    funding:

  • NSF grants CCF-0430065 and CCF-0429901: "Collaborative Research: Fundamentals and Algorithms for Streaming Meshes."
  • National Geospatial-Intelligence Agency/Defense Advanced Research Projects Agency Award HM1582-05-2-0003
  • Alfred P. Sloan Research Fellowship