Soil sealing – also called imperviousness – is defined as a change in the nature of the soil leading to its impermeability. Soil sealing has several impacts on the environment, especially in urban areas and local climate, influencing heat exchange and soil permeability ; therefore, soil sealing monitoring is crucial especially for the Mediterranean coastal areas, where soil degradation combined with drought periods and fires contributes to desertification risk.
The project Mediterranean Soil Sealing, promoted by ESA European Space Agency, aims to provide specific products related to soil sealing presence and degree over the Mediterranean coastal areas by exploiting EO data with an innovative methodology capable to optimise and scale-up their use with other non-EO data. Such products have to be designed to allow – concerning current practices and existing services – a better characterisation, quantification and monitoring within time of soil sealing over the Mediterranean basin, supporting users and stakeholders involved in monitoring and preventing land degradation.
The targeted products are high resolution maps of soil sealing over the Mediterranean coastal areas (within 20km from the coast) for the 2018-2022 time period, at yearly temporal resolution with a targeted spatial resolution of 10m.
Following the outcome of user survey available here, the following table reports the land cover features that are included in the soil sealing definition and the land cover features that are excluded.
Table: The land cover features included in the soil sealing definition.
| N. | Land cover feature |
| 1. | Housing areas (even with scattered houses) |
| 2. | Areas associated with transport systems (airports, harbours, railway yards, parking lots) |
| 3. | Roads |
| 4. | Railway tracks associated with other impervious surfaces (i.e., inside built-up area) |
| 5. | Industrial, commercial areas, factories, energy production, and distribution facilities |
| 6. | Impervious areas associated with land cover categories are characterised by not-sealed areas, such as, e.g., allotment gardens, cemeteries, sport, and recreation areas, campsites, excluding green areas associated with them. |
| 7. | Single (farm) houses (where possible to identify from satellite imagery) |
| 8. | Paved borders of water edges |
| 9. | Paved greenhouses |
| 10. | Construction sites with discernible evolving built-up structures |
| 11. | Artificial grass-covered sport pitches |
| 12. | Green roofs |
| 13. | Mines and quarries |
| 14. | Railway tracks outside built-up areas |
| 15. | Construction sites without discernible evolving built-up structures |
| 16. | Long-term plastic-covered soil in agricultural areas (e.g. non-paved greenhouses) |
| 17. | Solar panel parks |
Table: The land cover features excluded from the soil sealing definition.
| N. | Land cover feature |
| 1. | Natural, artificial, and cultivated vegetated areas |
| 2. | Un-vegetated or sparsely vegetated areas |
| 3. | Un-vegetated agricultural fields, arable land |
| 4. | Vineyards, fruit plantations (also if they have a plastic cover) |
| 5. | Grass surfaces used for sports of any kind |
| 6. | Sand, sandpits |
| 7. | Seasonal plastic coverage on agricultural fields |
| 9. | Dump sites |
Product Specifications
In the following tables are reported the specification of the two products foreseen: the Soil Sealing Degree and the Reversible Soil Sealing.
Table: Soil Sealing Degree product specifications
| Content |
| Soil Sealing Degree |
| Geographic coverage |
| 20 km buffer landward from the coastline of Mediterranean basin |
| Input data sources |
| Sentinel-1 and Sentinel-2 time series and other ancillary data |
| Methodology of classification |
| Deep and machine learning classification using features extracted from Sentinel-1 and 2 data, in particular: biophysical properties, Pantex data as well as coherence and speckle divergence information |
| Spatial resolution and coverage |
| Pixel resolution 10m, grid to fully conform to the Sentinel-2 images |
| Minimum Width of linear features |
| NA |
| Coordinate Reference System |
| European ETRS89 LAEA projection |
| Accuracy, Constraints |
| 90% overall and 85% in both producer and user accuracy |
| Accuracy assessment approach |
| Stratified random sampling |
| Methodology of aggregation |
| NA |
| Frequency |
| 1 per year from 2018 to 2022 |
| Availability |
| Raster data downloadable from the project website. The data will also be available from a dedicated online dashboard for visualization and geo analytic analysis. |
| Delivery/Output format |
| Geotiff raster data format |
| Data type |
| Unsigned 8-bit |
| Raster coding |
| 0: non-sealed areas 1-100: sealed area, degree of soil sealing values 254: unclassifiable (clouds, shadows etc.) 255: outside AOI |
| Product Scale (image/mapping products) |
| 1:10000 |
| Metadata |
| XML metadata files according to INSPIRE standards |
| Quality Control Process Applied |