Monday, 7 November 2005
8

Development of Automated Coding Descriptors for the National Wetland Inventory.

Alexis Sandy1, John Galbraith1, Patricia Donovan1, and Ralph Tiner2. (1) Virginia Tech, Dept. of Crop & Soil Env. Sci., 239 Smyth Hall (0404), Blacksburg, VA 24061, (2) Fish and Wildlife Service, 300 Westgate Center Drive, Hadley, MA 01035

National Wetland Inventory (NWI) maps are the definitive source maps for wetland resources in the United States. To date, the NWI program has produced wetland maps for approximately 90 percent of the contiguous United States and 35 percent of Alaska. Currently, 46 percent of the initial mapped area has undergone a digital revision and enhancement. Despite the wealth of knowledge that these wetlands maps provide, they lack hydrogeomorphic and other characteristics that are needed for assessment of wetland functions. With the use of geographic information systems (GIS) and geospatial databases, the NWI production unit in Hadley, MA has begun to develop a digital map database, integrating functional descriptors. The addition of a landscape descriptor will allow wetland functions to be predicted and detailed characterization to be performed at watershed levels. However, the updating process is still conducted manually and there is a need to automate some of the steps in order to speed up the revision process. The purpose of this research is to produce automated functions for GIS software that relate existing public domain data and recently-updated NWI map codes with classes of NWI wetland polygons within the Coastal Plain physiographic region of Virginia. Digital elevation models (DEM), USGS hydrography data, Digital Ortho Quarter Quads (DOQQ), and 1:24,000 topographic maps will be used to identify and automate landscape position classes of NWI polygons. In addition, DEM, hydric soils data, hydrography data, and hydrologic connectivity will be combined to define and automate water flow paths for NWI polygons. The expected outcome is a set of coding functions and methods using modern software tools and public domain data sources. Progress on function development will be reported and explained. Preliminary field validation will be conducted to test the accuracy of the NWI maps and the two automated functions.

Handout (.pdf format, 9683.0 kb)

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