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Use of CEMS data through CREODIAS


The CREODIAS platform hosts the most of complete archives of the Sentinel satellites, as well as the European coverage of Landsat satellites. Besides satellite data, Copernicus Services data sets are also hosted on the platform. Copies of the Copernicus Land (CLMS), Marine (CMEMS), Atmosphere (CAMS) and Emergency (CEMS) datasets are currently stored on CREODIAS. By bringing all these datasets to one access location, users of CREODIAS can easily combine a wide variety of data sets that will suit their needs. In this case study, combined use of CEMS Emergency and Sentinel data is shown.

CEMS data access

Accessing CEMS data stored on the platform is done in this example through a Windows VM. The CREODIAS EOdata repository is mounted as a network drive and can be accessed as any drive through File Explorer. This shows an immediate advantage of using a VM on the CREODIAS platform, there is no need to download any satellite data to your computer, they are already present and ready to be used for further processing inside the VM. Suitable satellite imagery can be searched in the CREODIAS Finder and be accessed by copying the file path into ESA SNAP, QGIS or any other preferred software and start working on it straightaway.

The CEMS data repository is not yet searchable through CREODIAS Finder, although it is foreseen this will be realised in the next few months. Currently, the CEMS data repository can be searched through the CEMS data hub. The Rapid Mapping datasets are stored on CREODIAS categorised by emergency type, be it floods, fires, earthquakes etc. For each emergency activation, Rapid Mapping data is available as shapefiles of the event itself (flood extent, fire scar, etc.), transportation systems, hydrography, land use, etc.


Screenshot of CEMS data in a Windows VM environment

Example use case

In this use case, activation with CEMS ID-number EMSR397 is visualised. This event is described as a flash flood event in the Segre River Basin in Eastern Spain. The event occurred on the 22nd of October 2019. In this use case we will check whether there is still ongoing flooding in the days after the event. From the data folder of the event, the shapefiles with the flood extent, local hydography and built-up areas are loaded into QGIS. From this data it appears the flash floods were spread out over an area east of the town of Lleida in a number of agricultural fields, not covering a large continuous area.


CEMS data loaded into QGIS

This data is compared with Sentinel-2 data that is loaded into QGIS through a WMS request, using the Sentinel Hub OGC WMS access tools accessed through the CREODIAS EO Hub. There are several Sentinel-2 data products that can be loaded through a WMS access, in this case it is chosen to load the Normalised Differential Water Index (NDWI), which shows the presence or absence of water. This layer is very well suited to detect water in placed where it normally is not. The NDWI image is based on a Sentinel-2 image dated 28/10/2019, so six days after the flooding event. From this image it shows no fields are flooded anymore.


CEMS data and Sentinel-2 based NDWI data loaded into QGIS

Use potential

This use case shows how Copernicus Services CEMS data as well as Sentinel-2 data stored on CREODIAS can be utilised simultaneously, without any need to download data locally. This provides opportunity to use these datasets storage and computationally efficient, without any need for large storage and processing facilities on premise.


Full copies of the Copernicus Services archives (CAMS, CEMS, CLMS, CMEMS) data are stored on CREODIAS. These datasets are stored alongside the Sentinel satellites data on the CREODIAS data repository. For example, the CEMS Emergency Mapping data repository can be accessed through a VM hosted on CREODIAS directly. CEMS spatial data can be loaded into any GIS directly and used in any further analysis, for example by comparison with post-event satellite data.