Terrain changes from images acquired on opportunistic flights by SFM photogrammetry
Luc Girod1, Christopher Nuth1, Andreas Kääb1, Bernd Etzelmüller1, and Jack Kohler21Department of Geosciences, University of Oslo, Postboks 1047 Blindern, 0316 Oslo, Norway 2Norwegian Polar Institute, Framsenteret, Hjalmar Johansens gate 14, 9296 Tromsø
Received: 03 Oct 2016 – Accepted for review: 29 Oct 2016 – Discussion started: 31 Oct 2016
Abstract. Structure from motion (SfM) photogrammetric techniques are emerging as powerful tools for surveying, at very high spatial and temporal resolution, geomorphological objects undergoing relatively rapid change, such as glaciers, moraines, or landslides. Modern software and computing power allows production of accurate data from low-cost surveys, compared to traditional photogrammetry conducted from dedicated fixed-wing aircraft missions. We present a method to take advantage of light-transport flights conducting other missions to opportunistically collect imagery for geomorphological analysis. We test and validate an approach in which we attach simple cameras and GNSS receivers to a helicopter to collect data when the flight path covers an area of interest. The novelty in our method is the ability to link GNSS data to images without a physical or electronic link. As a proof of concept, we conducted two test surveys in September 2014 and 2015 over the glacier Midtre Lovénbreen and its forefield, in northwestern Svalbard. We were able to derive elevation change estimates complementing in-situ mass balance measurements using the glaciological method. Furthermore, we detect and analyze a number of processes in the proglacial area, including thermokarst and the evolution of water channels.
Girod, L., Nuth, C., Kääb, A., Etzelmüller, B., and Kohler, J.: Terrain changes from images acquired on opportunistic flights by SFM photogrammetry, The Cryosphere Discuss., doi:10.5194/tc-2016-228, in review, 2016.