GIS Analytical Tools and Other Resources

The Wetlands Mapper is the primary public interface to the National Wetlands Inventory (NWI) geospatial dataset and is designed to deliver easy-to-use map-like views of the Nation's wetland and deepwater resources. Advanced users can incorporate the NWI Web Mapping Services into their applications, and users that leverage GIS in their wetland workflows can download NWI geospatial data for analysis. NWI data provides users with a robust and powerful dataset that is used to address questions and support decision-making in various fields. The tools provided here were developed for users interested in using downloaded NWI data to perform basic analyses, but without the time or resources to develop their own tools. Examples of different types of analysis using NWI data can be found on our NWI Use Highlights page.

This page also provides helpful links to other resources for GIS analysis, including data clearinghouses, cartographic aids, and other habitat analysis toolboxes.

Wetlands Python Toolbox

The python toolbox in this download provides a suite of tools to help select, process, and analyze NWI data. These tools can help the user limit the data by geographic extent or wetland classification. This user-friendly toolbox was programmed with python code. No coding or model-builder experience is required; the tools are run with a graphic user interface. The tools provided will select the wetland features that contain the habitat(s) you are interested in, clip those features to a study area of your choice, and calculate summary statistics to analyze the distribution and size of the wetlands within the study area. For more detailed information about the tools in this toolbox, please see the Wetlands Tools Python Toolbox.

Data required to implement this workflow includes NWI wetland data and a feature class or shapefile of your study area (common examples are counties, USGS watersheds, or ecoregions).

The NWI dataset and associated tables are updated on a biannual basis, typically in October and May. To ensure you have the most up to date information, please refer to the published date in the metadata, and download new data and tables regularly. Tools included in this download are listed below.

Selecting tools:

  • Select by System (5 Cowardin Systems)
  • Select by Wetland Type (8 NWI Wetland Types)
  • Select by Wetland Habitat (15 NWI Wetland Habitats)

Processing tools:

  • Buffer (creates a feature surrounding wetland features within a specified distance)
  • Dissolve (creates aggregated wetland features by combining adjacent polygons)
  • Clip (restricts wetland features to a separate polygon or polygons (e.g. counties, watersheds, project boundaries)

Analytical tools:

  • Summary Statistics (provides some basic areal statistics for wetlands features)
  • Wetlands Density (provides raw acreage statistics and an acreage ratio for wetland features in a study area (e.g. counties, watersheds, project boundaries)
  • Attribute Frequency (provides a count of how frequently unique attributes occur in the wetlands data)

NWI Python Toolbox Download Package - Last updated: September 2019 (ARC GIS 10 and Pro Compatible)

GIS Resources

For more information about GIS data, cartography, and geographic data please refer to the resources below.

Note: Links to non-Service Web sites do not imply any official FWS endorsement of the opinions or ideas expressed therein, or guarantee the validity of the information provided.