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Is it possible to export a surface and terrain model files from an aerial, LiDAR point cloud (LAS) set?

I am using SAGA GIS for very basic operations, but I couldn't find this option (and I have a hunch SAGA GIS should support both operations).

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    By definition, you can't "export" a DTM from a point cloud. You can however interpolate to get a surface. There are a number of different methods for that, but one of the more widely used is IDW.
    – Martin
    Commented Mar 4, 2014 at 11:35
  • Thanks Martin! Does that mean I have to write my own code to do it? Not that it's difficult, but I'd rather not implement it if it's been done somewhere else and is publicly available.
    – teodron
    Commented Mar 4, 2014 at 12:05
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    I'm afraid it's been a while since I used SAGA, but I'd be very surprised if there weren't functions for that already. There is in QGIS at least. Remember to filter your data for ground points and outliers etc before interpolating, or you will get strange results.
    – Martin
    Commented Mar 4, 2014 at 12:11
  • Point cloud tools, open source at code.google.com/p/point-cloud-tools
    – rych
    Commented Mar 6, 2014 at 6:30
  • I know I am late but anyway. I love SAGA-GIS so here comes the solution... geostat-course.org/system/files/pc_processing_with_saga.pdf enjoy!
    – Jens
    Commented Nov 28, 2014 at 21:34

4 Answers 4

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There's a great tutorial from Wichmann et al. (2012) 1 here.

Using SAGA GIS to process LiDAR data and create nDSM and DTM is a 6-step procedure very easy to follow.

Reference:

1- Wichmann, V.; Conrad, O.; Jochem, A.: LiDAR Point Cloud Processing with SAGA GIS. In: Hamburger Beiträge zur Physischen Geographie und Landschaftsökologie 20, S. 81-90.

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    please @Constantine We prefer longer answers and not link only answers. Also there is a "URL" button to make them pretty. If you would explain what you learned from the tutorial and clean up your answer please. Using the gis.stackexchange.com/help FAQ may give some direction.
    – Brad Nesom
    Commented Dec 30, 2014 at 17:08
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LAStools! http://rapidlasso.com/lastools/

Super fast LiDAR processing tools (either standalone or as ArcGIS toolbox). They have a las2dem tool which can create output in any of these formats: BIL, ASC, IMG, FLT, XYZ, DTM, TIF, PNG or JPG.

Enjoy.

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    LAStools is no longer open source/freeware. Commented Mar 4, 2014 at 15:35
  • @JeffreyEvans Aww damn really? Haven't used them in a while. Thanks for the heads up.
    – pvdev
    Commented Mar 4, 2014 at 16:16
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    @thehealingprocess Jeffrey is right, you're required to buy a license if your input is over 1.5M points. Otherwise, the tools will add some noise to the input (the author did not disclose any details about this "small" noise).
    – teodron
    Commented Mar 4, 2014 at 16:40
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    @thehealingprocess I am not sure (haven't measured it yet :( ), but, indeed.. a shame. Oh well, a lot of work was invested into the development of LasTools, so I presume Martin Isenburg & co. are entitled to it :).
    – teodron
    Commented Mar 4, 2014 at 17:07
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    Bob McGaughey, USFS-PNW, is still actively developing FUSION. If you dig into the users manual you will discover that there are a number of command line tools available independent of the GUI. These include ground filters, interpolation and a variety of binned lidar metrics. It is completely free. forsys.cfr.washington.edu/fusion/fusionlatest.html Commented Mar 4, 2014 at 18:15
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You may check GRASS GIS 7 which comes with some Lidar support:

http://grasswiki.osgeo.org/wiki/LIDAR#Micro-tutorial_for_LIDAR_data_analysis

See therein: - DEM/DSM separation the simple way by selection of Lidar returns - DEM/DSM separation the more complex way

The plan is to expand the Wiki page furthermore (users may edit).

Edit: Here is an online course available:

"Analyze multiple return lidar data and create DEM and DSM", see http://courses.ncsu.edu/mea582/common/GIS_anal_grass/GIS_Anal_grgeomorph1_2014.html

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A newer option is the lidR library in R. https://github.com/Jean-Romain/lidR

It is specifically designed for forest analysis but includes general purpose lidar processing tools. I like the way it combines sophisticated algorithms with straightforward syntax and quick visualizations (plot and plot_3D).

Check out the grid_terrain command for extracting a dem from a las point cloud. It gives you a choice of three interpolation methods: idw, tin, and kriging. Note: This assumes your las file is already classified with ground points identified. If not run lasground first.

The link below provides a list of all commands with examples.

https://cran.r-project.org/web/packages/lidR/lidR.pdf

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