Development of an automatic delineation of cliff top and toe on very irregular planform coastlines (CliffMetrics v1.0)

Payo, A., Jigena Antelo, B., Hurst, M. , Palaseanu-Lovejoy, M., Williams, C., Jenkins, G., Lee, K., Favis-Mortlock, D., Barkwidth, A. and Ellis, M. A. (2018) Development of an automatic delineation of cliff top and toe on very irregular planform coastlines (CliffMetrics v1.0). Geoscientific Model Development Discussions, 11(10), pp. 4317-4337. (doi: 10.5194/gmd-2018-83)

Abstract

We describe a new algorithm that automatically delineates the cliff top and toe of a cliffed coastline from a Digital Elevation Model (DEM). The algorithm builds upon existing methods but is specifically designed to resolve very irregular planform coastlines with many bays and capes, such as parts of the coastline of Great Britain. The algorithm automatically and sequentially delineates and smooth shoreline vectors, generates orthogonal transects and elevation profiles with a minimum spacing equal to the DEM resolution, and extracts the position and elevation of the cliff top and toe. Outputs include the non-smoothed-raster and smoothed-vector coastline, normals to the coastline- (as vector shapefiles), xyz profiles (as comma-separated-value files), and the cliff top and toe (as point shape files). The algorithm also automatically assesses the quality of the profile and omits low-quality profiles (i.e. extraction of cliff top and toe is not possible). The performance of the proposed algorithm is compared with an existing method, which was not specifically designed for very irregular coastlines, and to hand-digitized boundaries by numerous professionals. Also we assess the reproducibility of the results using different DEM resolutions (5m, 10m and 50m), different user defined parameter-sets related to the degree of coastline smoothing, and the threshold used to identify the cliff top and toe. The model output sensitivity is found to be smaller than hand-digitized uncertainty. Code and a manual are publicly available on a github repository.

• Item Type: Articles
• Additional Information: This work was funded by the Natural Environment Research Council (NERC) as part of the (BLUEcoast) project (NE/N015649/1).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Hurst, Dr Martin
• Authors: Payo, A., Jigena Antelo, B., Hurst, M., Palaseanu-Lovejoy, M., Williams, C., Jenkins, G., Lee, K., Favis-Mortlock, D., Barkwidth, A., and Ellis, M. A.
• College/School: College of Science and Engineering > School of Geographical and Earth Sciences
• Journal Name: Geoscientific Model Development Discussions
• Publisher: Copernicus Publications
• ISSN: 1991-962X
• ISSN (Online): 1991-962X
• Published Online: 11 June 2018
• Copyright Holders: Copyright © 2018 The Authors
• First Published: First published in Geoscientific Model Development Discussions 11(10):4317-4337
• Publisher Policy: Reproduced under a Creative Commons License