It portrays coastal-inland gradients, and better reflects the heterogeneity of vegetation type distribution than the original CAVM. The greater spatial resolution of the Raster CAVM allowed more detailed mapping of water-bodies and mountainous areas. The analysis presented here summarizes the area, geographical distribution, elevation, summer temperatures, and NDVI of the map units.
The map was reviewed by experts familiar with their particular region, including many of the original authors of the CAVM from Canada, Greenland (Denmark), Iceland, Norway (including Svalbard), Russia, and the U.S. The units resulting from the classification were modeled to the CAVM types using a wide variety of ancillary data. In contrast to the original hand-drawn CAVM, the new map is based on unsupervised classifications of seventeen geographic/floristic sub-sections of the Arctic, using AVHRR and MODIS data (reflectance and NDVI) and elevation data. The Raster CAVM divides the original rock-water-vegetation complex map unit that mapped the Canadian Shield into two map units, distinguishing between areas with lichen- and shrub-dominated vegetation. The legend has 16 vegetation types, glacier, saline water, freshwater, and non-arctic land. The Raster CAVM uses the legend, extent and projection of the original CAVM. We present a new version of the CAVM, building on the strengths of the original map, while providing a finer spatial resolution, raster format, and improved mapping. However, the relatively coarse resolution and vector format of the map were not compatible with many other data sets.
The Circumpolar Arctic Vegetation Map (CAVM), produced in 2003, has been widely used as a base map for studies in the arctic tundra biome. Land cover maps are the basic data layer required for understanding and modeling ecological patterns and processes.
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