The landscape physiography map was derived from topographic data, regional physiographic maps, and visual interpretation of the AVHRR false-CIR image. Physiographic codes were assigned to each of the vegetation polygons. For Greenland, Russia and the United States, detailed landscape maps formed the basis of the vegetation polygons (see vegetation mapping section). However, these regional landscape maps did not have a uniform legend and could not be easily combined. The detailed landscape categories were combined into the ten general categories most useful in creating the vegetation map which were further combined into five categories for the final map (plains, hills, mountains, glaciers (including nunataks), and water (including lakes, lagoons, and ocean)). The plateau category was merged with the either the hill category (500 m elevation), because it was interpreted differently in different portions of the map. Riparian areas were also not consistently defined in different parts of the map. Many riparian areas, though of great ecological importance, were also too narrow to map (less than 5 km width). For these reasons, the riparian physiography category (and the riparian vegetation category) were mapped as linear features, not polygons.
Elvebakk, A. 1999. Bioclimate delimitation and subdivisions of the Arctic. Pages 81-112 in I. Nordal and V. Y. Razzhivin, editors. The Species Concept in the High North - A Panarctic Flora Initiative. The Norwegian Academy of Science and Letters, Oslo.
Yurtsev, B. A. 1994. Floristic divisions of the Arctic. Journal of Vegetation Science 5:765-776.