Converting LIDAR .las Point Clouds for Viewing in SAGA GIS using PDAL

Recent versions of SAGA GIS no longer support importing files in the .las format. However, a .las file can be converted using PDAL’s writers.text module into a text file format, which in turn can be imported in SAGA. For this example, we will begin with a .las file projected in a state plane CRS that is the output of my post Reprojecting LIDAR .las files to Latitude/Longitude to State Plane Example.

1. Open a new text file named las2xyz.json in the same directory as your .las file and paste the following into it:

   {
     "pipeline": [
       {
         "type": "readers.las",
         "filename": "20131013_usgs_olympic_wa_10TDT310990.las"
       },
       {
         "type": "writers.text",
         "order": "X,Y,Z",
         "keep_unspecified": "false",
         "quote_header": "false",
         "delimiter": ",",
         "filename": "20131013_usgs_olympic_wa_10TDT310990.txt"
       }
     ]
   }

2. Now run the pipeline. This may take a while. Once it completes, you should now see the converted .txt file in the working directory.

   pdal pipeline las2xyz.json
   ls -hs -1 
   total 1.1G
   227M 20131013_usgs_olympic_wa_10TDT310990.las
   148M 20131013_usgs_olympic_wa_10TDT310990.laz
   745M 20131013_usgs_olympic_wa_10TDT310990.txt
   4.0K las2xyz.json
   4.0K lat_lng_WA_S_FIPS_ft_reprojection.pipeline.json
   

3. Let’s perform a quick sanity check on this new file:

   less 20131013_usgs_olympic_wa_10TDT310990.txt
   X,Y,Z
   803169.892,932562.842,2093.730
   803170.060,932566.158,2093.070
   803178.839,932573.593,2054.360
   803170.851,932564.554,2093.700
   803225.508,932562.372,2043.070
   803232.723,932560.928,2040.090
   803232.361,932562.222,2041.790
   803232.443,932564.117,2041.470
   803234.863,932568.358,2030.210
   803235.004,932568.206,2034.440
   803236.294,932567.895,2028.310
   
   

4. Open SAGA GIS. From the Geoprocessing menu, select File -> Tables -> Import -> Import Text Table with Numbers only
   
5. Select the .txt point cloud file that was created by PDAL, with the appropriate options as shown in the screenshot. Click Okay. Since the example text file used is nearly 1.0 GB in size, importing may take some time.
   
6. Once the text file has been imported as a table into SAGA, select Geoprocessing -> Shapes -> Point Clouds -> Conversion -> Point Cloud from Table.
   
7. Select the table that was created in the previous step, and then set the values for X/Y/Z to these columns from the table.
   
8. Afterwards, you will get the point cloud generated in your data sources.
   
9. From the Geoprocessing menu, select Visualization -> 3D Viewer -> Point Cloud Viewer. Select Z as the colored attribute.
   
   
10. Click Okay. The point cloud will be displayed in SAGA’s Point Cloud Viewer tool: