URL: www.nwi.fws.gov/ COST: Free for download. AGENCY: US Fish and Wildlife Service FORMAT: ArcInfo Interchange Format, DLG PROJECTION: UTM, NAD27

DESCRIPTION: The National Wetlands Inventory (NWI) of the U.S. Fish & Wildlife Service produces information on the characteristics, extent, and status of the Nation's wetlands and deepwater habitats. The National Wetlands Inventory Center (NWIC) has mapped 90 percent of the lower 48 states, and 34 percent of Alaska. About 44 percent of the lower 48 states, and 13 percent of Alaska are digitized.

DOWNLOAD: Go to wetlands.fws.gov/downloads.htm to download data. There are options for Arcdata or DLG data. Arcdata downloads an arc interchange (e00) file.

The data is organized by USGS 250k map name. It is advisable to have a USGS index book for the state in which your desired quads are located in order to find which 250k directory to access. Or, use the Wetlands Maps Database search form. To access it, go to www.nwi.fws.gov/downloads.htm and click on "View & Query NWI Maps Database Form." This can be used to determine the appropriate USGS quad names for download.

Another way to isolate quads is to use the USGS MapFinder web site edc.usgs.gov/Webglis/glisbin/finder_main.pl?dataset_name=MAPS_LARGE. This interface allows you to enter a place name, zip code, or to click on a map. Once you have zoomed in close enough, the names of the quads will be visible.

DLG Data: NWI 7.5' quad maps are available here. You can download wetland maps that have been digitized and converted to DLG (digital line graph) format. DLG is a vector format developed by the USGS and the files are NOT images (gifs, jpegs). Go to ftp://www.nwi.fws.gov/dlgdata/ and right-click on the folder of interest, choose "Copy to Folder" and select a location on your computer.

Arcdata: NWI maps that have been digitized and converted to ArcExport format are available. Once you have determined the name of the files to be downloaded, go to ftp://www.nwi.fws.gov/arcdata and select the appropriate files. Right-click and select "Copy To Folder." Select the location on your computer. Once the e00 files have been downloaded, it is necessary import them. ArcGIS8x cannot handle these files due to an old format. It is necessary to use the ArcView3x import utility to convert the e00 files to a shapefile, or to use PCArcInfo to convert the e00 files to a coverage. Two files are available for each quad name. The file with an f on the end is a point coverage. The other file is the NWI polygon coverage.

RESULTS: The NWI data is available in quads. The Haddam, CT quad is shown in the first figure. A close up of the quad is shown in the second graphic.

Back to Top

Comments or Suggestions? Email us at ewilson@canr.uconn.edu.

GTP Home | CLEAR Home | NEMO Home
News | Training | Research | Data | National Datasets | Contacts | Links

© University of Connecticut | Disclaimers and Copyright Statements