The accuracy of LIDAR data in terms of surface water hydraulic modelling
- Authors: Marjan Moderc, Regina Kolenc, Sašo Petan
- Citation: Acta hydrotechnica, vol. 30, no. 53, pp. 121-130, 2017.
- Abstract: In the spring of 2017 the Slovenian Environment Agency conducted a geodetic survey of the Sotla River as part of the FRISCO1 project. 270 river cross sections were measured, consisting of more than 5000 surveyed points. Those were used as a height reference for accurately evaluating the freely available Slovenian lidar dataset acquired in 2014. The analysis of the lidar data in the vicinity of water surfaces showed that the lidar data offer an extraction of near water surface topography with mean vertical accuracy of 0.5 m. Moreover, terrain that lies outside the wet areas can be extracted with an average 10 cm vertical accuracy, whereas a flat and open air surface can be extracted with an average 5 cm accuracy. This adds up to an average of 15% cross-section area decrease, causing similar decrease in river conductivity. The study concludes that for river flood modelling purposes, topographical elements such as flood plains, river sections with relatively shallow water, and linear infrastructure and hydraulic structures such as roads, railways, embankments, and dams could be obtained from the lidar data with mostly sufficient accuracy. On the other hand, elements such as deeper river sections, river crossings, and complex hydraulic structures could not be properly described using the available lidar data only. A simple and efficient tool for generating river cross sections from lidar data, called Xsection, has also been developed during the study and it is freely available for download and use.
- Keywords: LIDAR, hydraulic modelling, geodetic surveying, vertical accuracy, cross section
- Full text: a30mm.pdf
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