Creating better digital surface models from LiDAR points

Anahita Khosravipour, Martin Isenburg, Andrew K. Skidmore, Tiejun Wang

Research output: Chapter in Book/Report/Conference proceedingConference proceeding contributionpeer-review

2 Citations (Scopus)


In order to generate a Digital Terrain Model (DTM) that represents the bare terrain, LiDAR ground returns are typically Delaunay triangulated into a Triangular Irregular Network (TIN) that is then rasterized onto a grid at a user-specified resolution. In a similar same manner all of the first returns are usually interpolated in order to generate a Digital Surface Model (DSM) that represents the elevation of vegetation and objects. A Canopy Height Model (CHM) can be generated (1) either by subtracting the DTM raster from the DSM raster or (2) by replacing the elevation of each first return with its height-above-ground before interpolating them into a raster. This standard way of DSM and CHM generation has two drawbacks: (1) using only first returns means that not all LiDAR information is used meaning that some detail is missing and (2) using all first returns practically guarantees the formation of needle-shaped triangles in vegetated areas that appear as spikes in the TIN. These spikes represent extreme irregularities in the triangulated surface that result in "data pits" in the corresponding raster. These "pits" limit the utility of the DSM or CHM especially in forestry application, for example, to extract individual trees. We describe an algorithm that can generate significantly better Digital Elevation Models (DEMs) or Canopy Height Models (CHMs) from LiDAR point clouds compared to the "standard" approaches by constructing a spike-free TIN from all relevant returns taking the survey's pulse spacing into account. A working prototype of this algorithm was implemented and will soon be available as an integral LiDAR processing module of the LAStools software suite.

Original languageEnglish
Title of host publication36th Asian Conference on Remote Sensing 2015 (ACRS 2015)
Subtitle of host publicationfostering resilient growth in Asia : proceedings
EditorsAlfredo Mahar Lagmay
Place of PublicationJapan
PublisherAsian Association on Remote Sensing
Number of pages8
ISBN (Print)9781510817210
Publication statusPublished - 2015
Externally publishedYes
Event36th Asian Conference on Remote Sensing: Fostering Resilient Growth in Asia, ACRS 2015 - Quezon City, Metro Manila, Philippines
Duration: 19 Oct 201523 Oct 2015


Conference36th Asian Conference on Remote Sensing: Fostering Resilient Growth in Asia, ACRS 2015
CityQuezon City, Metro Manila


  • LiDAR points
  • interpolation
  • spike-free TIN
  • pit-free DSM
  • pulse spacing


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