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Fig. 7 | Journal of Applied Volcanology

Fig. 7

From: Volcanic plume height monitoring using calibrated web cameras at the Icelandic Meteorological Office: system overview and first application during the 2021 Fagradalsfjall eruption

Fig. 7

Extracting geometric information from aerial survey data. A Digital Elevation Model (DEM) from photogrammetry displayed as shaded relief, with the area visible from the camera location (red star) tinted blue. The solid blue line is the horizon visible from that location, extracted from the viewshed by taking the furthest visible point within azimuthal bins relative to the location of the camera. B The same viewshed overlain on the aerial survey orthophoto. C, D simulated view of the shaded relief and orthophoto from the camera location for a given calibration, with horizon points plotted in blue. Matching points between simulated view and real images can be used for calibration, while the blue horizon can be plotted over images and used to find the camera orientation and/or focal length. Aerial survey data from the Icelandic Institute of Natural History, Institute of Earth Sciences and National Land Survey of Iceland

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Journal of Applied Volcanology

ISSN: 2191-5040

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