This dataset defines the ecological areas of Alberta known as the Natural Regions and Natural Subregions, as defined in 2004/2005. The intended scale of use of this product is 1:250 000. This version is 2005 Final. Note that the Athabasca Plain subregion has been moved into the Boreal Natural Region and that the Boreal Highlands has now been split into Lower and Upper. Linework changes from the previous Natural Subregion delineation are due both to better information and refined subregion definitions. There is an accompanying report, published 2006. Update, June 2016: These data have been rectified to Alberta Township Survey (ATS) 4.1, using a "dissolve" of the Seed Zones of Alberta polygons (already rectified to ATS 4.1), by Natural Subregion Name. No polygon values were changed in this process; however, line work of some polygons along the provincial boundary has been adjusted slightly, for agreement with the ATS 4.1 provincial boundary polygon. The number of Alpine subregion polygons has decreased from 276 to 274 as a result of these minor adjustments.