Regional scale studies of glacial cirque metrics provide key insights on the (palaeo)environment related to the formation of these erosional landforms. The growing availability of high resolution terrain models means that more glacial cirques can be identified and mapped in the future. However, the extraction of their metrics still largely relies on time consuming manual techniques or the combination of, more or less obsolete, GIS tools. In this paper, a newly coded toolbox is provided for the automated, and comparatively quick, extraction of 16 key glacial cirque metrics; including length, width, circularity, planar and 3D area, elevation, slope, aspect, plan closure and hypsometry. The set of tools, named ACME (Automated Cirque Metric Extraction), is coded in Python, runs in one of the most commonly used GIS packages (ArcGIS) and has a user friendly interface. A polygon layer of mapped cirques is required for all metrics, while a Digital Terrain Model and a point layer of cirque threshold midpoints are needed to run some of the tools. Results from ACME are comparable to those from other techniques and can be obtained rapidly, allowing large cirque datasets to be analysed and potentially important regional trends highlighted.
Bibliographical noteThis paper is dedicated to Ian Evans. His passion for the analyses of glacial cirque metrics, along with his productivity and generosity, has not only allowed these landforms to be now recognised as key indicators of palaeoenvironmental conditions, but has also been an inspiration to many young researchers. We are also thankful to Clare Boston and 3 anonymous reviewers who greatly improved the original text; and to Richard Marston for his editorial assistance.
- glacial geomorphology
- glacial cirque