Digital Elevation Models (DEMs) after the Shovi (Caucasus) debris flow, 13 August 2023

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Introduction

On 4 August 2023, a large debris flow struck the mountain resort town of Shovi in Georgia. More on this event here : https://eos.org/thelandslideblog/the-4-august-2023-debris-flow-at-shovi-in-georgia

Two Pléiades stereo images were acquired after the event on 13 August 2023, thanks to the activation of the CIEST² (https://www.poleterresolide.fr/ciest-2-nouvelle-generation-2/) scheme. 2023-08-13a covers the lower part, 2023-08-13b the upper/source area.

We share here the Pléiades DEMs derived from these images. The collection includes four files:

Shovi_2023-08-13a_DEM_2m.tif

Shovi_2023-08-13a_DEM_20m.tif

Shovi_2023-08-13b_DEM_2m.tif

Shovi_2023-08-13b_DEM_20m.tif

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Methods

The Pléiades stereo-images were processed using the Ames Stereo Pipeline (ASP, Beyer et al., 2018), yielding a DEM in 2x2m and 20x20 m GSD and an orthoimage in 0.5x0.5m GSD. The processing was done using as only input the stereo-images and their orientation information, as Rational Polynomial Coefficients (RPCs). The parallel_stereo routine performs all the steps needed in the correlation of the stereo-images, yielding a pointcloud which is then interpolated using the routine point2dem. We used the block matching algorithm and the set of processing parameters from Marti et al. (2016)

Beyer, R. A., Alexandrov, O., and McMichael, S.: The Ames Stereo Pipeline: NASA’s Open Source Software for Deriving and Processing Terrain Data, Earth and Space Science, 5, 537–548, https://doi.org/10.1029/2018EA000409, 2018.

Marti, R. et al.: Mapping snow depth in open alpine terrain from stereo satellite imagery, The Cryosphere, 10(4), 1361–1380, doi:10.5194/tc-10-1361-2016, 2016.

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Data Specifications:

Cartographic projection: UTM zone 38N (EPSG:32638)

Origin of Elevation: meters above WGS84 ellipsoid

Raster data format: GeoTIFF

NoData value : -9999

Pléiades dataset includes only DEMs because a licence needs to be signed with CNES to access Pléiades imagery. Please contact the authors for further information on this.

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Acknowledgements:

Pléiades images were provided under the CIEST² initiative (CIEST2 is part of ForM@Ter (https://en.poleterresolide.fr/) (Pléiades © CNES 2023, distribution AIRBUS DS)

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Dataset Attribution:

This dataset is licensed under a Creative Commons CC BY-NC 4.0 International License (Attribution-NonCommercial).

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Citation:

Please cite this repository as :

Berthier E. (2023). Digital Elevation Models (DEMs) after the Shovi flood (Caucasus), 13 August 2023, Dataset distributed on Zenodo: 10.5281/zenodo.8252339