Point Cloud Options

Points clouds are a category of GIS data.  This forms allow manipulation of the LAS point cloud.

  Tabs provided detailed option selection:
Main controls on the bottom of the form, always visible.  This window display results on the map. 

For a 3D view, you have several options on this set of controls.  These work on the current map area, and you should restrict the map area to what you need, because both of these options load a lot of data into memory which is slow operations down.
  • LAS lidar color coding
  • OpenGL Point cloud
    • 3 views will export elevation, classification, intensity, and RGB if that is part of the point cloud.  If more that one cloud is checked, they will be merged.
    • Class Cats: each classfication category will be exported in its own layer, which you can turn on and off on the 3D viewer.  If more that one cloud is checked, they will be merged.
    • Main button on the bottom will use the current color coding, and export each cloud as a separate layer.
  • Slice: EW and NS slices through the point cloud
General tab. 
  • Thinning for OpenGL, and slices
  • KML vertical offset, to put the points above the landscape. 
  • KML vertical offset: distance above the ground for KML exports.
  • Bad point filter: if this is set, you can ignore points classified as noise, and also points classified as overlay.
  • Assume LAS 1.4 for data sets using an older version of the LAS specs, but including the newer classification categories, which is relatively common
  • Open only tiles on map.  If you make the map larger, no new tiles will be added.
  • Immediate zoom to cloud on opening files
  • Immediate map after opening: turn off if you have very large point clouds that will draw slowly, and you want to subset first
  • Automatic lidar redraws: turn off for a very large point cloud
  • Show point density of mean grid creation
  • Log output
  Files tab. 
Tools tabMany of these options require that the base map in use have a DEM associated with it, which will determine the size of the grid created.
 

Stats tab:

  • Histograms/Counts: histograms for elevation and intensity, and a count of the returns in each category, and by return number.
  • Zero classification: merge all LAS files in the current files listing into a single file, with the classifications all reset to zero.
  • RGB Palette:
  • Split by class: create new files by classification (vegetation, buildings, ground, non_ground, unclassified, and other)
  • Recenter files: recenter all coordinates so that multiple files share the same values.  This is designed for use with Cloud Compare, and not at this time to create usable LAS files for further analysis.
  • Subset/tile: recursively quarter files until all file sizes are under a specified value;
  • Zero fields : set the following fields to zero: Intensity, ReturnFlags, ScanAngle, UserData, PointSourceID
  • Cell statistics: compute elevation statistics for every cell in the DEM on which the point cloud is displayed
  • Recompute: recreate the index files for the lidar directories (all those currently selected).  Should only be necessarily if the index becomes corrupted, or you add new files to the directory.

 

 


Last revision 6/16/2020