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LAS format and processing DTMs from tins and local binning

LAS format and processing DTMs from tins and local binning. Arrowsmith. LAS files: industry standard format. Example of EarthScope Northern California LiDAR data from Mill Gulch along the San Andreas Fault (NCALM data processed at and downloaded from OpenTopography ).

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LAS format and processing DTMs from tins and local binning

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  1. LAS format and processingDTMs from tins and local binning Arrowsmith

  2. LAS files: industry standard format

  3. Example of EarthScope Northern California LiDAR data from Mill Gulch along the San Andreas Fault (NCALM data processed at and downloaded from OpenTopography)

  4. Grids in ArcMap for context

  5. LASTOOLS

  6. Install LASTOOLS somewhere like C:

  7. Install LASTOOLS arc toolbar

  8. las2shp using LASTOOLS toolbar

  9. Need to define the projection for the shapefile

  10. Need to make a las dataset in Arc

  11. LAS dataset in ArcMap

  12. LAS file in ArcMap

  13. LAS file in ArcScene

  14. resampling raster DEM j triangulating interpolating i temporary TIN Generating DEMs from LIDAR LIDAR points Isenburg, et al., 2006

  15. Interpolation Methods • Inverse Distance Weighting (IDW) • Natural Neighbors • Kriging • Splines • TIN • linear • quintic • … Isenburg, et al., 2006

  16. Streaming TIN output StreamingComputationof Delaunay Triangulation ImmediateRasterizationof Streaming TIN output final DEM to disk small bufferin main memory store elevation rasters to temporary files(grouped by rows) DEMGenerationviaTINStreaming read points from disk Isenburg, et al., 2006

  17. 50,394×30,500 DEM 3 GB(binary, BIL, 16 bit, 20 ft) raster DEM Example Result 500,141,313 Points 11 GB(binary, xyz, doubles) LIDAR points  on a household laptop with two harddisks   in 67 minutes   64 MB of main memory   270 MB temporary disk space  Isenburg, et al., 2006

  18. blast2dem

  19. BLAST2DEM DEM

  20. BLAST2DEM DEM Strip: “…it's a licensing issue. to get around it (for academic or personal use) you can simply use lastile to make it small enough and then run blast2dem on smaller tiles and then recomposite with GDAL. “—Martin Isenburg

  21. Windows version: http://lidar.asu.edu/points2grid.html

  22. An Efficient Implementation of a Local Binning Algorithm for Digital Elevation Model Generation of LiDAR/ALSM Dataset (Kim, et al., 2006)

  23. Need comma delimited file for P2G

  24. 1 m local binning dem

  25. 1 m radius shot density

  26. 1 m radius shot density

  27. Ground returns only (TIN)

  28. Ground returns only (1 m radius IDW)

  29. Points over bare earth surface

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