Towards a webcam-based snow cover monitoring network: methodology and evaluation
Snow cover variability has a significant impact on climate and the environment and is of great socioeconomic importance for the European Alps. Terrestrial photography offers a high potential to monitor snow cover variability, but its application is often limited to small catchment scales. Here, we p...
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Copernicus Publications
2020
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Online Access: | https://doi.org/10.5194/tc-14-1409-2020 https://www.the-cryosphere.net/14/1409/2020/tc-14-1409-2020.pdf https://doaj.org/article/803763dd21344b3aa1e65a2d070db04d |
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fttriple:oai:gotriple.eu:oai:doaj.org/article:803763dd21344b3aa1e65a2d070db04d 2023-05-15T18:32:19+02:00 Towards a webcam-based snow cover monitoring network: methodology and evaluation C. Portenier F. Hüsler S. Härer S. Wunderle 2020-04-01 https://doi.org/10.5194/tc-14-1409-2020 https://www.the-cryosphere.net/14/1409/2020/tc-14-1409-2020.pdf https://doaj.org/article/803763dd21344b3aa1e65a2d070db04d en eng Copernicus Publications doi:10.5194/tc-14-1409-2020 1994-0416 1994-0424 https://www.the-cryosphere.net/14/1409/2020/tc-14-1409-2020.pdf https://doaj.org/article/803763dd21344b3aa1e65a2d070db04d undefined The Cryosphere, Vol 14, Pp 1409-1423 (2020) geo envir Journal Article https://vocabularies.coar-repositories.org/resource_types/c_6501/ 2020 fttriple https://doi.org/10.5194/tc-14-1409-2020 2023-01-22T19:24:07Z Snow cover variability has a significant impact on climate and the environment and is of great socioeconomic importance for the European Alps. Terrestrial photography offers a high potential to monitor snow cover variability, but its application is often limited to small catchment scales. Here, we present a semiautomatic procedure to derive snow cover maps from publicly available webcam images in the Swiss Alps and propose a procedure for the georectification and snow classification of such images. In order to avoid the effort of manually setting ground control points (GCPs) for each webcam, we implement a novel registration approach that automatically resolves camera parameters (camera orientation; principal point; field of view, FOV) by using an estimate of the webcams' positions and a high-resolution digital elevation model (DEM). Furthermore, we propose an automatic image-to-image alignment to correct small changes in camera orientation and compare and analyze two recent snow classification methods. The resulting snow cover maps indicate whether a DEM grid is snow-covered, snow-free, or not visible from webcams' positions. GCPs are used to evaluate our novel automatic image registration approach. The evaluation reveals a root mean square error (RMSE) of 14.1 m for standard lens webcams (FOV<48∘) and a RMSE of 36.3 m for wide-angle lens webcams (FOV≥48∘). In addition, we discuss projection uncertainties caused by the mapping of low-resolution webcam images onto the high-resolution DEM. Overall, our results highlight the potential of our method to build up a webcam-based snow cover monitoring network. Article in Journal/Newspaper The Cryosphere Unknown Principal Point ENVELOPE(-63.431,-63.431,-64.912,-64.912) The Cryosphere 14 4 1409 1423 |
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geo envir |
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geo envir C. Portenier F. Hüsler S. Härer S. Wunderle Towards a webcam-based snow cover monitoring network: methodology and evaluation |
topic_facet |
geo envir |
description |
Snow cover variability has a significant impact on climate and the environment and is of great socioeconomic importance for the European Alps. Terrestrial photography offers a high potential to monitor snow cover variability, but its application is often limited to small catchment scales. Here, we present a semiautomatic procedure to derive snow cover maps from publicly available webcam images in the Swiss Alps and propose a procedure for the georectification and snow classification of such images. In order to avoid the effort of manually setting ground control points (GCPs) for each webcam, we implement a novel registration approach that automatically resolves camera parameters (camera orientation; principal point; field of view, FOV) by using an estimate of the webcams' positions and a high-resolution digital elevation model (DEM). Furthermore, we propose an automatic image-to-image alignment to correct small changes in camera orientation and compare and analyze two recent snow classification methods. The resulting snow cover maps indicate whether a DEM grid is snow-covered, snow-free, or not visible from webcams' positions. GCPs are used to evaluate our novel automatic image registration approach. The evaluation reveals a root mean square error (RMSE) of 14.1 m for standard lens webcams (FOV<48∘) and a RMSE of 36.3 m for wide-angle lens webcams (FOV≥48∘). In addition, we discuss projection uncertainties caused by the mapping of low-resolution webcam images onto the high-resolution DEM. Overall, our results highlight the potential of our method to build up a webcam-based snow cover monitoring network. |
format |
Article in Journal/Newspaper |
author |
C. Portenier F. Hüsler S. Härer S. Wunderle |
author_facet |
C. Portenier F. Hüsler S. Härer S. Wunderle |
author_sort |
C. Portenier |
title |
Towards a webcam-based snow cover monitoring network: methodology and evaluation |
title_short |
Towards a webcam-based snow cover monitoring network: methodology and evaluation |
title_full |
Towards a webcam-based snow cover monitoring network: methodology and evaluation |
title_fullStr |
Towards a webcam-based snow cover monitoring network: methodology and evaluation |
title_full_unstemmed |
Towards a webcam-based snow cover monitoring network: methodology and evaluation |
title_sort |
towards a webcam-based snow cover monitoring network: methodology and evaluation |
publisher |
Copernicus Publications |
publishDate |
2020 |
url |
https://doi.org/10.5194/tc-14-1409-2020 https://www.the-cryosphere.net/14/1409/2020/tc-14-1409-2020.pdf https://doaj.org/article/803763dd21344b3aa1e65a2d070db04d |
long_lat |
ENVELOPE(-63.431,-63.431,-64.912,-64.912) |
geographic |
Principal Point |
geographic_facet |
Principal Point |
genre |
The Cryosphere |
genre_facet |
The Cryosphere |
op_source |
The Cryosphere, Vol 14, Pp 1409-1423 (2020) |
op_relation |
doi:10.5194/tc-14-1409-2020 1994-0416 1994-0424 https://www.the-cryosphere.net/14/1409/2020/tc-14-1409-2020.pdf https://doaj.org/article/803763dd21344b3aa1e65a2d070db04d |
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op_doi |
https://doi.org/10.5194/tc-14-1409-2020 |
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The Cryosphere |
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14 |
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4 |
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1409 |
op_container_end_page |
1423 |
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