Sea areas should not be included in the surface area, but islands in the sea should be included. In a GIS system it is for practical reasons not feasible to include polygons of all islands because of the great accuracy and large scale needed. It is thus proposed that there can be no link between surface areas measured in a GIS and the official areas used for calculations. The latter areas must continue to be stored as variables in info tables.
Islands should be included in the land area. The definition of islands should be consistent with the coastline definition.
Eurostat, "Empfehlungen zur Festlegung eines einheitlichen Verfahrens für die Berechnung der Fläche von Gebietseinheiten - Ausgabe 1999; Recommendations for a harmonised definition of calculation of surface area of territorial units, 1999 edition; Recommandations pour une définition harmonisée du calcul de la superficie des unités territoriales - Édition 1999", Office for Official Publications of the European Communities, Luxembourg, 1999, p.16