Classification of Wetlands and Deepwater Habitats of the United States - U.S. Fish and Wildlife Service Data Standard

Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of Wetlands and Deepwater Habitats of the United States.  U.S. Fish and Wildlife Service, FWS/OBS-79/31, Washington, D.C. 131 pp.

Coordination of Wetlands Data Collection:

• National Wetlands Inventory:  A Strategy for the 21^st Century. 2001.  U.S. Fish and Wildlife Service, Branch of Habitat Assessment, Arlington, VA. 13 pp.

• National Standards and Quality Components For Wetlands, Deepwater and Related Habitat Mapping.  2004. U.S. Fish and Wildlife Service, Branch of Habitat Assessment, Arlington, VA. 18 pp.

• Technical Procedures for Wetland and Deepwater Habitat Mapping. 2004.  In Manuscript. U.S. Fish and Wildlife Service, Branch of Habitat Assessment, Arlington, VA. 46 pp.

National Wetlands Inventory Home Page - online maps, map information, wetland information, and more!

The Service’s topical wetland maps are graphic representations of the type, size and location of wetlands and deepwater habitats in the United States. These maps, produced from the analysis of high altitude imagery, collateral data sources and field work, represent reconnaissance level information on the location, type, and size of wetlands habitats. Published wetland maps, at the nominal scale of 1:24,000 for the conterminous U.S. and 1:63,360 for Alaska, comply with National Map Accuracy Standards. Due to the margin of error inherent in the use of imagery, detailed on-the-ground inspection of any particular site may result in revision of the wetland boundaries or classification established through image analysis.

The accuracy of image interpretation depends on the quality of the imagery, experience of the image analysts, amount and quality of the collateral data, and extent of ground truth verification conducted in the field. Metadata should be consulted to determine the date of the source imagery and any problems that may have occurred during the mapping process.

Wetlands or other mapped features may have changed since the date of the imagery and/or field work. There may be occasional differences in polygon boundaries or classifications between the information depicted on the map and the actual conditions on site. 

Wetland Resource Attribution and Verification Tools:  In cooperation with the U.S. Geological Survey (USGS), customized tools have been developed for resource mapping using geodatabases in ArcMap. These customized Attribution and Verification tools, installation instructions, and user information are available for download at http://www.fws.gov/wetlands/data/Tools.html.

For the purpose of adapting the wetland classification system to map form, a series of alphanumeric codes has been developed to correspond with the classification nomenclature that best describes the habitat. The customized Attribution Tools are extensions to the Environmental Systems Research Institute, Inc. (ESRI) ArcMap desktop application for all map-based tasks including cartography, map analysis, and editing.  To run these tools, any workstation must be capable of running the ArcGIS family of software, including ArcDesktop and ArcWorkstation. 

The Attribution tools are ‘resource mapping’ tools designed to attribute map features that may depict wetlands, riparian areas, uplands or other natural resource features. These tools can also serve as a reference for uncommon or rarely used codes or to assist users who are not familiar with the alphanumeric wetland mapping codes. The main Attribution Tool contains the entire hierarchal scheme for the classification of wetlands and deepwater habitats (Cowardin et al. 1979).

The Verification tools automate (to the extent possible) the quality control functions necessary to ensure an accurate geodatabase by addressing geopositional errors, digital anomalies, and some logic checks that make use of the geographic information system.

Wetlands Mapper:  This new version of the wetlands mapping application, developed in collaboration with the USGS, promotes a greater awareness of wetlands map data applications and delivers easy-to-use, map-like views of America's wetland resources in a digital format. For ease of viewing the map information, wetland types are displayed in aggregation with similar classifications (e.g., all freshwater emergent wetlands are displayed as a single color category). The web site currently serves wetland data for 26,000 USGS quadrangles (approximately 42 percent of the conterminous U.S.) in a seamless ArcSDE geodatabase. Additional data for the entire state of Hawaii, 13 percent of Alaska, and portions of Puerto Rico and the U.S. Trust Territories will be available soon. 

Attribute Extraction (ATX):  This tool provides a short or long description of the Cowardin wetland types based on the attribute codes, as well as the plant species associated with wetland habitats.