Automatic extraction of landslide flow direction using geometric processing and DEMs

TitleAutomatic extraction of landslide flow direction using geometric processing and DEMs
Publication TypeBook Chapter
Year of Publication2015
AuthorsNiculita, Mihai
Secondary AuthorsJasiewicz, Jaroslaw, Zbigniew Zwoliński, Helena Mitasova, and Tomislav Hengl
Book TitleGeomorphometry for Geosciences
Pagination201 - 203
PublisherBogucki Wydawnictwo Naukowe, Adam Mickiewicz University in Poznań - Institute of Geoecology and Geoinformation
CityPoznań, Poland
ISBN Number978-83-7986-059-3
Abstract

Landslides are mass wasting landforms which occur due to various triggering factors, and generate a specific morphology. This morphology is governed by the flow of the material downslope. While the majority of the landslide have the length bigger than the width (flows, slides, deep-seated landslides), in certain topographic conditions, landslides with width larger than length can exist (slides and deep-seated landslides). We target such a case, by creating a methodology to automatically determine the direction of the flow, in such a way that the oriented bounding box polygon to be aligned downslope, and the length of the landslide polygon to be determined. After the application of the first step of the algorithm, in which the direction of landslide flow is assessed using the altitude range of the midpoints of the long (length candidates) and short (width candidates) sides of the landslide oriented bounding box (for a landslide to be long the altitude range between the opposite long sides need to be greater than the range for the opposite short sides), manual check was used to assess the results. This check showed that the majority of the landslides were correctly classified, either as long or wide, but in the long landslide class there are in fact wide class landslides which are situated on valley sides  with steep channels. These landslides have the altitude range between the short sides smaller than the altitude range between the long sides, although the direction of the flow is along the short side. To correctly classify the flow direction for these landslides, we have used the slope length computed on the DEM patches of the landslide polygons. Where the slope length is greater than the landslide width determined in the first phase and the landslide is classified as long, the landslide class is changed to wide, and vice versa. By this approach we manage to correctly classify the landslides as long or wide in the landslide inventory of the Moldavian Plateau, Romania (24 263 landslides).

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