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

<p>===========================</p><p>Introduction</p><p>On 4 August 2023, a large debris flow struck the mountain resort town of Shovi in Georgia. More on this event here&nbsp;: <a href="https://eos.org/thelandslideblog/the-4-august-2023-debris-flow-at-shovi-in-georgia">https://eos.org/thelandslideblog/the-4-august-2023-debris-flow-at-shovi-in-georgia</a></p><p>Two Pléiades stereo images were acquired after the event on 13 August 2023, thanks to the activation of the CIEST² (<a href="https://www.poleterresolide.fr/ciest-2-nouvelle-generation-2/">https://www.poleterresolide.fr/ciest-2-nouvelle-generation-2/</a>) scheme.</p><p>We share here the Pléiades DEMs derived from these images. The collection includes four files:</p><p>Shovi_2023-08-13a_DEM_2m.tif</p><p>Shovi_2023-08-13a_DEM_20m.tif</p><p>Shovi_2023-08-13b_DEM_2m.tif</p><p>Shovi_2023-08-13b_DEM_20m.tif</p><p>===========================</p><p>Methods</p><p>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 semi global matching algorithm and the set of processing parameters from Deschamps-Berger et al. (2020)</p><p>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.</p><p>Deschamps-Berger, C., Gascoin, S., Berthier, E., Deems, J., Gutmann, E., Dehecq, A., Shean, D., and Dumont, M.: Snow depth mapping from stereo satellite imagery in mountainous terrain: evaluation using airborne laser-scanning data, The Cryosphere, 14, 2925–2940, https://doi.org/10.5194/tc-14-2925-2020, 2020.<br><br>===========================</p><p>Data Specifications:</p><p>Cartographic projection: UTM zone 38N (EPSG:32638)</p><p>Origin of Elevation: meters above WGS84 ellipsoid</p><p>Raster data format: GeoTIFF</p><p>NoData value&nbsp;: -9999</p><p>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.</p><p>===========================</p><p>Acknowledgements:&nbsp;</p><p>Pléiades images were provided under the CIEST² initiative (CIEST2 is part of ForM@Ter (https://en.poleterresolide.fr/) (Pléiades © CNES 2023, distribution AIRBUS DS)</p><p>===========================</p><p>Dataset Attribution:</p><p>This dataset is licensed under a Creative Commons CC BY-NC 4.0 International License (Attribution-NonCommercial).</p><p>===========================</p><p>Citation:</p><p>Please cite this repository as described below:</p><p>Etienne Berthier. (2023). Digital Elevation Models (DEMs) after the Shovi flood (Caucasus), 13 August 2023</p>