Last Return

Last Return in LiDAR is the term that denotes the last significant return of a LiDAR pulse from the objects on the Earth's surface. The number of returns may be several, depending on whether a single laser pulse strikes vegetation, buildings, terrain, and any other objects. In many cases, the last return is related to the Earth surface and is usually used for analysis of the terrain and its elevation.

Last-return data is helpful for finding the ground points located under other elements such as vegetation and building constructions. This type of data is used for creating Digital Terrain Models (DTMs), Digital Elevation Models (DEMs), contour maps, and 3D representation of the area. It is also useful for analysis of the forest cover, topography, surveys, floods, infrastructure construction, and environmental researches.

The understanding of the concept of last returns is essential while working with LiDAR data because the return data helps to understand the structure and elevation of the territory better. With the help of last returns together with the first, intermediate and single returns one can get precise geospatial data for GIS and remote sensing purposes.