Elevations at the speed of light
The firm employs a Riegl LiDAR system capable of scanning from 1500m. From this range the coverage is excellent and it is possible to acquire extensive areas cost effectively.A 69Mp Rolleimetric AIC Pro is tied to the system providing the ability to acquire high resolution imagery simultaneous to the LiDAR survey.
LiDAR TECHNOLOGY IN BRIEF
LiDAR (Light Detection and Ranging)involves the direct measurement of terrain from an airborne platform by laser. The unit receives the reflected light from the ground and calculates the distance from the aircraft by determining the time taken for the laser light to travel from the aircraft to the surface and back again. All LiDAR units require a high grade Inertial Navigation System (INS) and use the data to calculate a height for each laser return.
Can LiDAR see “through” vegetation?
This is one of the biggest misnomers that are often not appreciated. If you can’t see the ground from the air the LiDAR won’t either! Unlike RADAR, LiDAR is based on light that cannot penetrate vegetation.
None the less, if there is even a small break in vegetation canopy the LiDAR will almost certainly hit it and one can record a ground strike. LiDAR therefore, lends itself very well to generating contours under commercial forest. In this case there are always breaks in the trees that the LiDAR will measure and under the trees there is normally little if any undergrowth so this constitutes a valid ground strike. LiDAR is however, VERY poor at establishing heights under fully grown sugar cane. In this instance the strike could be anywhere on the cane and even if there is a valid ground strike it is impossible to separate from the surrounding cane with post processing. In this case a photogrammetric survey would be more appropriate.