U.S. Fish & Wildlife Service, National Wetlands Inventory
NWI has been producing wetland maps and geospatial wetland data for the United States since the mid-1970s. The focus has been on two fronts: 1) map or digital database preparation and delivery to the public, and 2) projecting and reporting on national wetland trends using a probability-based sampling design. The status of mapping has been made available through various media throughout NWI's 30-year history (e.g., state atlases, regional status maps, and now through the internet via the Wetlands Mapper online tool).