Proceedings of the 2017 4th International Conference on Information and Communication Technologies for Disaster Management (ICT-DM)



These are the proceedings of the 4th International Conference on Information and Communication Technologies for Disaster Management (ICT-DM), hosted by the Chair for Information Systems and Supply Chain Management and ERCIS Competence Center for Crisis Management at the University of Münster. Information and Communication Technologies have become key drivers of Crisis and Disaster Management with its uses ranging from the assessment of potential risks, provision of effective response during the occurrence of such disasters, as well as the evaluation in post-disaster phases to enhance the overall management before the next inevitable event takes place. Moreover, crisis management is a team effort and its improvement depends on bringing together academics and practitioners to learn from each other and develop innovative and valuable ideas together. ICT-DM aims at doing just that and we have been excited to welcome colleagues from around the world to share the latest developments in research and practice. We appreciate the lively exchange of experience and knowledge from the researchers and their practitioner counterparts during the conference.
The automatic extraction of valley lines (VLs) from digital elevation models (DEMs) has had a long history in the GIS and hydrology fields. The quality of the extracted results relies on the geometrical shape, spatial tessellation, and placement of the grids in the DEM structure. The traditional DEM structure consists of square grids with an eight‐neighborhood relationship, where there is an inconsistent distance measurement between orthogonal neighborhoods and diagonal neighborhoods. The directional difference results in the extracted VLs by the D8 algorithm not guaranteeing isotropy characteristics. Alternatively, hexagonal grids have been proved to be advantageous over square grids due to their consistent connectivity, isotropy of local neighborhoods, higher symmetry, increased compactness, and more. Considering the merits above, this study develops an approach to VL extraction from DEMs based on hexagonal grids. First, the pre‐process phase contains the depression filling, flow direction calculation, and flow accumulation calculation based on the six‐neighborhood relationship. Then, the flow arcs are connected, followed by estimating the flow direction. Finally, the connected paths are organized into a tree structure. To explore the effectiveness of hexagonal grids, comparative experiments are implemented against traditional DEMs with square grids using three sample regions. By analyzing the results between these two grid structures via visual and quantitative comparison, we conclude that the hexagonal grid structure has an outstanding ability in maintaining the location accuracy and bending characteristics of extracted valley networks. That is to say, the DEM‐derived VLs based on hexagonal grids have better spatial agreement with mapped river systems and lower shape diversion under the same resolution representation. Therefore, the DEMs with hexagonal grids can extract finer valley networks with the same data volume relative to traditional DEM.
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