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)
example LIDAR data (sample files) in LAS format:
related publications:
related downloads:
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: