This map was digitized using 2010 true-color 1-meter National Agriculture Imagery Program (NAIP) aerial imagery. The minimum mapping unit is 0.25 acre with a 10-foot minimum width. The map classification is the same as used for the Delta Vegetation and Land Use map that was based on 2002 imagery and finalized in 2007. The map [ds292] can be obtained here: http://bios.dfg.ca.gov/dataset_index.asp. The report, which provides the classification detail can be obtained here: https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=18211. Because Liberty Island was mapped as part of the Delta mapping effort, changes over the eight year period between imagery dates can be seen, most obviously land accretion and erosion and invasion of the non-native water primrose, Ludwigia. Mappers used reconnaissance-level data to refine and verify the map. The data were collected at 48 points during two field missions: 1) August 9, 2012 by land covering the levee on the western boundary of the area, and 2) August 28 - 29, 2012 by boat. All vegetation samples were marked with GPS units and can serve as long-term monitoring points. Photos taken at these GPS points can be used for future monitoring. A database of field data and the digital photos are archived at the office of the Vegetation Classification and Mapping Program (VegCAMP) of DFW. This map has not been assessed for accuracy, but over 25 percent of the polygons were visited during field reconnaissance. Lead staff of the program cross-checked and edited the map attributes and delineations.
