Vegetation delineations based on photo interpretation and formal vegetation classification plus change detection. This update by the Geographical Information Center (GIC) of the North State Planning and Development Collective at California State University, Chico is part of an ongoing triennial vegetation monitoring program for the Suisun Marsh. The project tracks changes in the Suisun Marsh vegetation over time to fulfill specific permit requirements of the Suisun Marsh Plan of Protection of 1984, the Suisun Marsh Preservation Agreement of 1986, and the 2015 Suisun Marsh Preservation Agreement. This is the seventh update using the current mapping standards originally implemented in 1999. All of the previous vegetation maps from 1999 to 2015 can be viewed and downloaded using the online California Department of Fish and Wildlife (CDFW) Biogeographic Information and Observation System (BIOS); the links to the associated reports are included in the map metadata. Minimum mapping unit (MMU): Typically, the minimum mapping size is 0.25 acres. However, the photo interpreters use their best judgment to determine if a stand below 0.25 acre should be separately delineated. For example, a smaller polygon would be appropriate for any new visible occurrence of a non-native species of concern, such as Phragmites australis, Arundo donax, Carpobrotus edulis, Eucalyptus spp., and Lepidium latifolium. Minimum mapping width: There are many long and narrow polygons within the Suisun Marsh study area, most of which are roads, ditches, levees, and sloughs. The minimum mapping width is typically 10 feet; however, if small sections of a stand fell below the minimum width, the polygon was not split. More information can be found in the project report, which is bundled with the vegetation map published for BIOS here: https://filelib.wildlife.ca.gov/Public/BDB/GIS/BIOS/Public_Datasets/2900_2999/ds2963.zip, and the report is available for download separately at: https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=218048.