Resolution Sensitivity of a Compound Terrain Derivative as Computed from LiDAR-Based Elevation Data

New technologies such as Light Detection And Ranging (LiDAR) provide high resolution digital elevation data. These data offer new possibilities in the field of terrain modelling and analysis. However, not very much is known about the effects when these data are used to compute broadly applied terrain derivatives. In this paper the sensitivity of the Topographic Wetness Index (TWI) and its two constituting components gradient and Specific Catchment Area (SCA) regarding the resolution of LiDARbased elevation data is examined. For coarser resolutions a shift in the TWI distribution to higher values is noted. TWI distributions at different resolutions differ significantly from each other. These findings have an impact on aspatial and spatial modelling based on the TWI. DOI: https://doi.org/10.1007/978-3-540-72385-1_5 Posted at the Zurich Open Repository and Archive, University of Zurich ZORA URL: https://doi.org/10.5167/uzh-77854 Accepted Version Originally published at: Straumann, Ralph K; Purves, Ross S (2007). Resolution sensitivity of a compound terrain derivative as computed from LiDAR-based elevation data. In: Fabrikant, Sara I; Wachowicz, Monica. The European information society. Leading the way with Geo-information. Berlin: Springer, 87-109. DOI: https://doi.org/10.1007/978-3-540-72385-1_5 Resolution Sensitivity of a Compound Terrain Derivative as Computed from LiDAR-Based Elevation Data Ralph K. Straumann and Ross S. Purves Department of Geography, University of Zurich – Irchel, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland {rsm, rsp}@geo.unizh.ch Abstract. New technologies such as Light Detection And Ranging (LiDAR) provide high resolution digital elevation data. These data offer new possibilities in the field of terrain modelling and analysis. However, not very much is known about the effects when these data are used to compute broadly applied terrain derivatives. In this paper the sensitivity of the Topographic Wetness Index (TWI) and its two constituting components gradient and Specific Catchment Area (SCA) regarding the resolution of LiDAR-based elevation data is examined. For coarser resolutions a shift in the TWI distribution to higher values is noted. TWI distributions at different resolutions differ significantly from each other. These findings have an impact on aspatial and spatial modelling based on the TWI. New technologies such as Light Detection And Ranging (LiDAR) provide high resolution digital elevation data. These data offer new possibilities in the field of terrain modelling and analysis. However, not very much is known about the effects when these data are used to compute broadly applied terrain derivatives. In this paper the sensitivity of the Topographic Wetness Index (TWI) and its two constituting components gradient and Specific Catchment Area (SCA) regarding the resolution of LiDAR-based elevation data is examined. For coarser resolutions a shift in the TWI distribution to higher values is noted. TWI distributions at different resolutions differ significantly from each other. These findings have an impact on aspatial and spatial modelling based on the TWI.