Credit: TU WIen
By Science Daily
Simply declaring a region as a nature protection area is not enough, regular monitoring of its ecological condition is also necessary. Since Nature protection areas already cover almost one fifth of the surface of the European Union, it is impossible to inspect such a vast area in the traditional way on foot. Therefore, new methods are being developed to monitor Europe’s nature protection areas from the air. Short laser pulses are sent to the ground, and information on the status of the habitat can be deduced from the reflected light signals using elaborate computer algorithms.
Laser Scanning from the Air
“The rules of the Natura 2000 network of nature protection areas request the evaluation of the conservation status of protected region at least every six years,” says Professor Norbert Pfeifer (Vienna University of Technology). “This can only be achieved with the help of remote sensing.”
Planes fly at an altitude of 500 to 2000 metres, scanning a strip 300 to 800 metres wide. About ten points per square meter are sampled using an infrared laser pulsing half a million times a second. The pulses are reflected and return to the plane. From their travel time, the exact distance between the plane and the ground can be calculated, creating a detailed 3D map of the landscape.
Software Identifies Structure
“Our team has developed special classification software which can use this data to distinguish different types of vegetation,” says Norbert Pfeifer. Even disturbing factors such as weeds and vehicle tracks can be identified.