The advanced filtering of Lidar Data can be applied from the Digitizer tool, or when using the Lidar Toolbars Automatic Classification and Feature Extraction tools.
To access this option from the Digitizer, select a set of Lidar Points, then right-click with the digitizer and under Advanced Selection options choose the option to Filter Selected Lidar Points By Elev/Color/Class etc...
The Filter Lidar Points dialog (below) contains options to filter lidar points by elevation, height above ground, color, classification, return type, point source id, scan angle and NDVI or NDWI if colored by raster calculation results.
The advanced lidar filtering options are also available while running lidar tools, including Create Elevation Grid, Automatic Classification tools , Extract Vector Features and Lidar LAS/LAZ Export Options by choosing the Filter Points... , Filter Points by Elev/Class/etc..., or Filter Lidar Points to Use by Elevation/Class/Color/Etc... buttons.
To filter by elevation or height above ground, enter a range of elevation or height values.
To filter points by color select 'Keep Lidar Points with Colors Below' and use the color picker or RGB values to select or define the colors you would like to keep, use the slider in this section to set fuzzy tolerances for your selection.
Use the Point ID Source Filtering field to create a white list of Point Source IDs to export. Lidar Classifications or Return Types may be selected to keep. The list of classifications and return types will be generated from the selected or loaded data itself.
These options allow filtering or unselecting Lidar points based on elevation
These options allow filtering or unselecting Lidar points based on Height Above Ground.
This option allows for selecting Lidar Points based on RGB values. Add a color and use the slider to determine how similar colors must be to be included in the Filter.
Filter or unselect Lidar points by unchecking Classes.
Select Lidar points based on Point Source ID. Point Source IDs identify the flight used when collecting the Data.
Filter or unselect Lidar points by unchecking Return Types.
Filter by the acceptable scan angle specified in the point attributes.
Filter by the intensity value of the point features. The intensity value comes from the strength of the return signal, and helps to identify differences in surface textures similar to bands of color imagery.
Filter data based on the calculated point density. This is calculated on load based on other points in the layer.
If the points have Red and IR (Infrared) values associated with them, they may be filtered by NDVI value. Normalized Difference Vegetation Index values range from -1 to 1. For more information see NDVI
Filter by NDWI values. This uses the Green and NIR channels to identify water in water bodies. For more information see NDWI
*Some filtering options will only be available to users with the Lidar Module registered.