Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Skip to content

Terrestrial Ecosystems - Land Surface Forms of the Conterminous United States

Metadata Updated: October 28, 2023

The U.S. Geological Survey (USGS) has generated land surface form classes for the contiguous United States. These land surface form classes were created as part of an effort to map standardized, terrestrial ecosystems for the nation using a classification developed by NatureServe (Comer and others, 2003). Ecosystem distributions were modeled using a biophysical stratification approach developed for South America (Sayre and others, 2008) and now being implemented globally (Sayre and others, 2007). Land surface forms strongly influence the differentiation and distribution of terrestrial ecosystems, and are one of the key input layers in the ecosystem delineation process. The methodology used to produce these land surface form classes was developed by the Missouri Resource Assessment Partnership (MoRAP). MoRAP made modifications to Hammond's (1964a, 1964b) land surface form classification, which allowed the use of 30-meter source data and a 1 km2 window for neighborhood analysis (True 2002, True and others, 2000). While Hammond's methodology was based on three variables, slope, local relief, and profile type, MoRAP's methodology uses only slope and local relief (True 2002). Slope is classified as gently sloping or not gently sloping using a slope threshold of 8%, local relief is classified into five classes (0-15m, 15-30m, 30-90m, 90-150m, and >150m), and eight landform classes (flat plains, smooth plains, irregular plains, escarpments, low hills, hills, breaks, and low mountains) were derived by combining slope class and local relief. The USGS implementation of the MoRAP methodology was executed using the USGS 30-meter National Elevation Dataset (NED) and an existing USGS slope dataset. In this implementation, a new land surface form class, the high mountains/deep canyons class, was identified by using an additional local relief class (> 400m). The drainage channels class was derived independently from the other land surface form classes. This class was derived using two of Andrew Weiss's slope position classes, "valley" and "lower slope" (Weiss 2001, Jenness 2006). The USGS implemented Weiss's algorithm using the 30-meter NED and a 1 km2 neighborhood analysis window. The resultant drainage channel class was combined into the final land surface forms dataset.

Access & Use Information

Public: This dataset is intended for public access and use. License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

Downloads & Resources


Metadata Created Date June 1, 2023
Metadata Updated Date October 28, 2023

Metadata Source

Harvested from DOI EDI

Additional Metadata

Resource Type Dataset
Metadata Created Date June 1, 2023
Metadata Updated Date October 28, 2023
Publisher U.S. Geological Survey
Identifier USGS:53b1dcaae4b03836de1947cb
Data Last Modified 20201117
Category geospatial
Category Tag 16E15F51 D96E 4051 9124 75665Abdc6Ff "Ecosystem Vulnerability","Biodiversity"
Public Access Level public
Bureau Code 010:12
Metadata Context
Metadata Catalog ID
Schema Version
Catalog Describedby
Harvest Object Id 44618394-9528-447a-b538-ef8580b20272
Harvest Source Id 52bfcc16-6e15-478f-809a-b1bc76f1aeda
Harvest Source Title DOI EDI
Metadata Type geospatial
Old Spatial -125.0,23.999926,-65.999444,49.500204
Publisher Hierarchy White House > U.S. Department of the Interior > U.S. Geological Survey
Source Datajson Identifier True
Source Hash f443dbf864fb65ddbccab437355878bf3f5bb7ed77829a596694d3ac25508cae
Source Schema Version 1.1
Spatial {"type": "Polygon", "coordinates": -125.0, 23.999926, -125.0, 49.500204, -65.999444, 49.500204, -65.999444, 23.999926, -125.0, 23.999926}

Didn't find what you're looking for? Suggest a dataset here.

An official website of the GSA's Technology Transformation Services

Looking for U.S. government information and services?