Precise Lidar Data And True-Ortho Images
Dipl.-Wirtschaftsing. Alexander Wiechert,
TopoSys GmbH
Obere Stegwiesen 26
88400 Biberach
a.wiechert@toposys.com
Abstract
With the increasing use of Geographic Information Systems (GIS), high resolution
images in a true-ortho projection become more and more significant. As 3D objects in
true-ortho projection are presented geometrically correct, they allow precise
superposition of any other geo-referenced information. Not long ago state-of-art was to apply true-ortho correction only for “relevant” objects e.g. by photogrammetry. The reason was that rectification of all objects needs a highly detailed elevation model, which was hardly available and / or too expensive. Precise Laserscanning now allows producing elevation models and RGB images in parallel, which are dense enough to apply true-ortho correction to all objects on large scale. A high resolution Lidar system supplemented by a line scanner forms the ideal survey equipment for ortho-image generation. The presentation describes Laserscanning systems which now allow precise Laserscanning suitable to generate true-ortho images. It shows a wide range of applications for which the of true-orthos calculated with help of a high precision elevation models acquired by Laserscanning currently have already been used successfully. Both, Lidar elevation models and true-orthos have been applied in projects related to simulation of floods, mapping of power line corridors and urban mapping.