This tool can be used to map areas of overlapping flightlines in an input LiDAR (LAS) file (`input`). The output raster file (`output`) will contain the number of different flightlines that are contained within each grid cell. The user must specify the desired cell size (`resolution`). The flightline associated with a LiDAR point is assumed to be contained within the point's `Point Source ID` property. Thus, the tool essentially counts the number of different Point Source ID values among the points contained within each grid cell. If the Point Source ID property is not set, or has been lost, users may with to apply the recover_flightline_info tool prior to running flightline_overlap.

It is important to set the `resolution` parameter appropriately, as setting this value too high will yield the mis-characterization of non-overlap areas, and setting the resolution to low will result in fewer than expected overlap areas. An appropriate resolution size value may require experimentation, however a value that is 2-3 times the nominal point spacing has been previously recommended. The nominal point spacing can be determined using the lidar_info tool.

Note that this tool is intended to be applied to LiDAR tile data containing points that have been merged from multiple overlapping flightlines. It is commonly the case that airborne LiDAR data from each of the flightlines from a survey are merged and then tiled into 1 km2 tiles, which are the target dataset for this tool.

Like many of the LiDAR related tools, the input and output file parameters are optional. If left unspecified, the tool will locate all valid LiDAR files within the current Whitebox working directory and use these for calculation (specifying the output raster file name based on the associated input LiDAR file). This can be a helpful way to run the tool on a batch of user inputs within a specific directory.

## See Also

classify_overlap_points, recover_flightline_info, lidar_info

## Function Signature

`def flightline_overlap(self, input_lidar: Lidar, resolution: float = 1.0) -> Raster: ...`

## Project Links

WbW Homepage User Manual Support WbW