The Digital Map of European Ecological Regions (DMEER) defines and describes specific ecological zones in Europe, based on European climatic, topographic and geobotanical data, together with the judgment of a large team of experts from several European nature-related institutions and the World Wildlife Fund (WWF). The Digital Map of European Ecological Regions (DMEER) relies on available vegetation information sources - the Natural Vegetation Map of Europe (Bonn, 1994) - and the topographic and climatic data The European Land (The European Land, Bunce, 1995). The cluster analysis model was used to place similar samples into clusters, which are arranged in a hierarchical structure called a dendrogram. These clusters or classes of ranking objects represent different ecological regions, and depending on their position in the dendrogram, or level of aggregation, they represent homogeneous sub-ecological regions, within the primary ecological regions. Subsequently, an agreement between the European Environment Agency (EEA), the European Topic Centre for Nature Conservation (ETC/NC) and the World Wildlife Fund (WWF) to arrive at two compatible maps of ecological regions for Europe, by the European Environment Agency (EEA) and the World Wildlife Fund (WWF), necessitated a series of compromises by both initiatives including the acceptance of the Digital Map of European Ecological Regions (DMEER) lines and units into the World Wildlife Fund (WWF), and the acceptance of the World Wildlife Fund (WWF) units into the Digital Map of European Ecological Regions (DMEER).