This collection of 10 separate geopackages contains the survey areas of the 1968-2015 Alaska Trumpeter Swan Surveys. The geopackages are named YYYY_AK_TRUS_Survey_Area.gpkg, where YYYY = survey year. Each year’s survey area consisted of a set of U.S. Geological Survey 1:63,360 scale quadrangle maps, where each map represented a potential sampling unit. The 1968-2005 surveys were designed to census the entire survey area, and thus all of the maps were surveyed in these years. The 2010 and 2015 surveys were stratified random samples (optimally allocated to minimize cost for a fixed variance); therefore, only a selected set of 100 maps were surveyed in these years. (Additional geopackages are available in the survey’s project archive that represent the 2010 and 2015 samples and are described elsewhere in the metadata.)
