A synergy of radar and optical data of Copernicus programme for landslide mapping.

摘要

Landslides represent one of the greatest natural disasters and that makes their research notably crucial. The development of Sentinel missions, which implemented by European Space Agency (ESA) for the operational needs of the Copernicus programme that is directed by the European Commission, gives a new impetus to Earth Observation, providing timely, operational, easily accessible, global coverage and robust datasets. It is worth mentioning that the specific datasets are freely available to users from a web-based system, called "Copernicus Open Access Hub". This work deals with the exploitation of Sentinel-1 radar data as well as Sentinel-2 optical data in order to map the sliding areas of an active landslide. The landslide occurred in January 2017 as result of snow melting, while the area is located in Western Peloponnese, Greece. The total length of the landslide zone was about 300 m with a head width of 330 m while the landslide material is constituted from three different geologic formations mirroring the complex geotectonic of the wider area. In that context, radar data as well as optical data were collected and processed appropriately. Concerning radar data, Sentinel-1 images before and after the occurrence of the slide were acquired and interferometric processed yielding to a displacement map through the estimation of vertical displacements. On the other hand, corresponding Sentinel-2 optical data before and after the landslide event were collected and they were submitted to digital processing techniques such as change detection analysis. The results of the two methodologies were compared and also, they were evaluated for their accuracy using the actual displacement values obtained from GPS and UAV surveys.