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Airborne Laser Scanning – Cost effective spatial data David Turton Manager – Aam Geoscan Email: D.Turton@aamgeoscan.com.au  David Jonas Production Manager, Aam Geoscan Email: D.Jonas@aamgeoscan.com.au AAM GEOSCAN, A Division of AAM Surveys Pty Ltd. 11 Wicklow Street, Kangaroo Point Qld. 4169 Australia Tel: +61738911033, Fax +61738911050
Abstract
Airborne Laser Scanning (ALS), also referred to as Light Detection and Ranging (LiDAR), is a remote sensing technology which enables large areas to be surveyed cost effectively using a fixed or rotory wing platform. The ALS instrument emits a stream of discrete points, up to 70,000 every second, which are reflected from objects the aircraft flies over. Post Processing of the data provides co-ordinates with height accuracies ranging from 0.1 metres to 0.5 metres and horizontal accuracies ranging from 0.3 metres to 1.5 metres, depending on flying height, GPS geometry and other project variables. Points reflected from the ground are separated from those above the ground. A closely spaced array of co-ordinated points can be obtained if required with point spacing ranging from 0.2 to 4.0 metres. This paper will briefly outline the technology before discussing two specific ALS applications in forestry and flood plain definition. Because ALS generates a large volume of data special attention must be given to data presentation. Some presentation options will be outlined. Planning an ALS project requires consideration of issues not encountered when planning data gathering using other methods. A selection of these issues will be discussed as will the causes of error in an ALS survey. |