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| Titel |
Optimisation of LiDAR derived terrain models for river flow modelling |
| VerfasserIn |
G. Mandlburger, C. Hauer, B. Höfle, H. Habersack, N. Pfeifer |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 13, no. 8 ; Nr. 13, no. 8 (2009-08-14), S.1453-1466 |
| Datensatznummer |
250011969
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| Publikation (Nr.) |
 copernicus.org/hess-13-1453-2009.pdf |
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| Zusammenfassung |
| Airborne LiDAR (Light Detection And Ranging) combines cost efficiency, high
degree of automation, high point density of typically 1–10 points per
m2 and height accuracy of better than ±15 cm. For all
these reasons LiDAR is particularly suitable for deriving precise Digital
Terrain Models (DTM) as geometric basis for hydrodynamic-numerical (HN)
simulations. The application of LiDAR for river flow modelling requires
a series of preprocessing steps. Terrain points have to be filtered and merged
with river bed data, e.g. from echo sounding. Then, a smooth Digital Terrain
Model of the Watercourse (DTM-W) needs to be derived, preferably considering
the random measurement error during surface interpolation. In a subsequent
step, a hydraulic computation mesh has to be constructed. Hydraulic simulation
software is often restricted to a limited number of nodes and elements, thus,
data reduction and data conditioning of the high resolution LiDAR DTM-W
becomes necessary. We will present a DTM thinning approach based on adaptive
TIN refinement which allows a very effective compression of the point data
(more than 95% in flood plains and up to 90% in steep areas) while
preserving the most relevant topographic features (height tolerance
±20 cm). Traditional hydraulic mesh generators focus primarily on
physical aspects of the computation grid like aspect ratio, expansion ratio
and angle criterion. They often neglect the detailed shape of the topography
as provided by LiDAR data. In contrast, our approach considers both the high
geometric resolution of the LiDAR data and additional mesh quality
parameters. It will be shown that the modelling results (flood extents, flow
velocities, etc.) can vary remarkably by the availability of surface
details. Thus, the inclusion of such geometric details in the hydraulic
computation meshes is gaining importance in river flow modelling. |
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