A priority was defined in the input data: first EU-Hydro geometry and, as auxiliary data, GSHHG dataset. The coastline of EU-Hydro represents the separation of land and water detected from Image2006 scenes. The status of the tidal wave depends on the date and time of the cloud-free scene used in Image 2006. The EU-Hydro do not cover the geographical requirements for EEA coastline. The EU-Hydro gaps are in Iceland, Canarias, Madeira, Azores, small islands (not represented in EU-DEM) and the northern Black Sea.
The creation process was focused on generating the coastline as line dataset and, later, as a secondary product, defining the polygon layer sea-land. The fundamental step of the workflow was the selection of sea features using a water mask polygon (value in EU-Hydro datasets = 255). The inland water bodies (fresh water) are rejected by this criteria, except the water bodies connected, at least by one point, to the sea (it is the case of some transitional water bodies). A few manual amendments to the dataset were necessary to meet the requirements from EU Nature Directives, Water Framework Directive and Marine Strategy Framework Directive. The line dataset consists of one single line for the whole coastline. The polygon dataset was derived from the parent line dataset by adding two straight lines, one North-to-South, at the East-most part of the parent dataset, and the second one West-to-East, at the South–most part of the parent dataset. The two straight lines are taken from the NGA-derived coastline produced by the ETC-BD in 2008.
EU-Hydro is a european-wide hydrological reference data set currently being developed under the Copernicus, http://www.copernicus.eu/, the European Earth Observation Programme.
GSHHG, "A Global Self-consistent, Hierarchical, High-resolution Geography Database", http://www.soest.hawaii.edu/pwessel/gshhg
NGA coastline, Coastline features from the National Geospatial-Intelligency Agency (NGA).
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