Airborne LiDAR has matured as an accurate and highly effective technology for the automated capture of terrain data through x, y and z points commonly referred to as point clouds. The point clouds represent the simplest form of ALS data which can then be classified into a variety of products including digital terrain models, contours and above ground features. ALS systems collect many more points than are necessary to define the terrain and hence generate large sized databases which are then filtered to create usable dataset sets. Depending upon the area of interest, size, shape and type of terrain, the parameters within the LiDAR system (pulse rate, swath width and scan angle) are set to achieve the best solution for each project.
Not only does the ALS system measure the time taken for each laser pulse to return to the sensor but it also measures the strength of the return signal. This data is referred to as intensity data and when greyscale readings are applied to the measurements, an intensity image is created, effectively delivering a medium resolution black and white ortho image. This greatly assists in validating classified datasets and identifying features in the surveyed area.
Elevation data provided by LiDAR is a perfect complement to high-resolution imagery, as it adds vertical dimension to enable 3-D modelling and much more.
Download our LiDAR brochure from the home page for more information.
The data below demonstrates ALS data of buildings and the Sky Tower. For more information please contact our Auckland office.