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wiki:pktools_lidar [2017/12/05 22:53] (current)
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 +====== Part 4 ======
 +
 +  * Introduction to LiDAR
 +  * Point data formats: ASCII, vector and LAS data
 +
 +===== Digital elevation models =====
 +
 +  * digital surface models (DSM)
 +  * digital terrain models (DTM)
 +  * vegetation height models (VHM)
 +
 +===== Open source software for processing LAS data =====
 +
 +  * las tools from Martin Isenburg (multiple license: partly open, partly commercial) [[http://​www.cs.unc.edu/​~isenburg/​lastools/​|lastools]]
 +  * las tools from Mateusz Loskot (BSD License): [[http://​www.liblas.org/​lastools.html|liblas]]
 +  * SPDLib from Pete Bunting: [[http://​www.spdlib.org/​doku.php?​id=spdlib:​examples:​examples|SPDLib]]
 +  * pktools creating and filtering DEM raster datasets from LAS files: [[http://​www.nongnu.org/​pktools/​html/​index.html|pktools]]
 +
 +====== Case study: LiDAR products in forestry ======
 +
 + * Input data: forest_31370.laz
 + * Create digital surface model (DSM)
 + * Create digital terrain model (DTM)
 + * Create vegetation height model (VHM)
 + * Create percentage height values (PHV)
 + * Create intensity map
 +
 +===== Set environment variables for input and output directories =====
 +
 +<​code>​
 +export INPUTDIR=...
 +export OTPUTDIR=...
 +</​code>​
 +
 +===== Extract basic information =====
 +
 +==== from LAZ file ====
 +
 +<​code>​
 +lasinfo $INPUTDIR/​forest_31370.laz
 +</​code>​
 +
 +==== from (APEX) hyperspectral dataset ====
 +
 +<​code>​
 +gdalinfo $INPUTDIR/​apex_ql.tif
 +</​code>​
 +
 +==== using pktools ====
 +
 +<​code>​
 +pkinfo -i $INPUTDIR/​apex_ql.tif -dx -dy -bb
 +</​code>​
 +
 +===== Create digital elevation models (DEM) =====
 +
 +==== Digital surface model (DSM) ====
 +
 +<​code>​
 +pklas2img -i $INPUTDIR/​forest_31370.laz -o $OUTPUTDIR/​forest_dsm.tif -a_srs epsg:31370 $(pkinfo -i $INPUTDIR/​apex_ql.tif -dx -dy -bb) -comp max
 +</​code>​
 +
 +==== Digital terrain model (DTM) ====
 +
 +<​code>​
 +pklas2img -i $INPUTDIR/​forest_31370.laz -o $OUTPUTDIR/​forest_dem_min.tif -a_srs epsg:31370 $(pkinfo -i $INPUTDIR/​apex_ql.tif -dx -dy -bb) -comp min
 +pkfilterdem -i $OUTPUTDIR/​forest_dem_min.tif -o $OUTPUTDIR/​forest_dtm.tif -f promorph -dim 3 -dim 17
 +</​code>​
 +
 +==== Vegetation height model (VHM) ====
 +
 +<​code>​
 +gdal_calc.py -A $OUTPUTDIR/​forest_dsm.tif -B $OUTPUTDIR/​forest_dtm.tif --outfile=$OUTPUTDIR/​forest_vhm.tif --calc="​(A>​B)*(A-B)"​
 +</​code>​
 +
 +==== Create percentage height values (PHV) ====
 +
 +<​code>​
 +pklas2img -i $INPUTDIR/​forest_31370.laz -o $OUTPUTDIR/​forest_profile.tif -a_srs epsg:31370 $(pkinfo -i input/​apex_ql.tif -dx -dy -bb) -comp profile -nbin 11
 +</​code>​
 +
 +==== Create intensity map ====
 +
 +<​code>​
 +pklas2img -i $INPUTDIR/​forest_31370.laz -o $OUTPUTDIR/​forest_intensity.tif -a_srs epsg:31370 $(pkinfo -i input/​apex_ql.tif -dx -dy -bb) -fir first -n intensity -ot UInt16
 +</​code>​
  
wiki/pktools_lidar.txt ยท Last modified: 2017/12/05 22:53 (external edit)