ALS stands for Airborne Laser Scanning, and consist of the emission of light pulses, reflection, and registration of the echo return. The procedure is also known as LiDAR, and is focused on the return of light. LiDAR stands for Light Detection and Ranging, and LiDAR datasets provides series of point based energy recordings reflecting ground height, canopy height and other canopy characteristics. When used as Airborne Laser Scanning, the emitted light pulse from the scanner can in some instances be some 200.000 pulses per second, resulting in processing procedures necessitating the handling of enormous amounts of point data.
In recent years, LiDAR has become a widely used tool for understanding both the cultural and natural landscape surrounding us. The result of this is, that new 3-dimensional point based LiDAR data is consistently being generated in a more precise and detailed version of raw point cloud form.
In order to cope with the increasing amount of spatial data and geo-information, a systematic and semi-automated process needs to be defined in order to control and handle these accumulated amounts of otherwise unrestrained information.
Thus ALS data provides 3-dimensional data of scanned area possible for interpolation and modelling. If proper processed and manipulated, data can be filtered to reveal different manipulated surfaces, such as only points of terrain in a landscape, which involves removing vegetation, construction, and all other features above bare-earth. This ability provides a new layer for understanding the landscape surrounding us, often revealing details that were long forgotten.