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)
Grids in ArcMap for context LASTOOLS Install LASTOOLS somewhere like C:
Install LASTOOLS arc toolbar las2shp using LASTOOLS toolbar
Need to define the projection for the shapefile Need to make a las dataset in Arc LAS dataset in ArcMap
LAS file in ArcMap LAS file in ArcScene
Generating DEMs from LIDAR resampling LIDAR points
triangulating raster DEM j
i temporary TIN interpolating
Isenburg, et al., 2006 Interpolation Methods
Inverse Distance Weighting (IDW)
Natural Neighbors Kriging Splines TIN linear
quintic Isenburg, et al., 2006
DEM Generation via TIN Streaming read points from disk Streaming
Computation of Delaunay Triangulation small buffer
in main memory Immediate Streaming Rasterization
TIN of Streaming output TIN
store elevation rasters to temporary files (grouped by rows) output final DEM
to disk Isenburg, et al., 2006 Example Result
500,141,313 Points 11 GB (binary, xyz, doubles) LIDAR points
50,394 30,500 DEM 3 GB (binary, BIL, 16 bit, 20 ft) raster DEM
on a household laptop with two harddisks in 67 minutes 64 MB of main memory 270 MB temporary disk spaceIsenburg, et al., 2006
blast2dem BLAST2DEM DEM
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
Windows version: http ://lidar.asu.edu/poin ts2grid.html
An Efficient Implementation of a Local Binning Algorithm for Digital
Elevation Model Generation of LiDAR/ ALSM Dataset (Kim, et al., 2006)
Need comma delimited file for P2G 1 m local binning dem 1 m radius shot density
1 m radius shot density Ground returns only (TIN)
Ground returns only (1 m radius IDW) Points over bare earth surface
