USGS - science for a changing world

Significant Topographic Changes in the United States

National Results

Results Info
National Results

States

Counties

Ecoregions

Watersheds

Managed Areas

Quadrangle Base Maps

1x1-Degree Tiles

Summary Statistics and Rankings
A primary objective of this study is to map (locate and describe) the extent of recent human geomorphic activity, as indicated by significant changes to the land surface topography. The inventory of topographic changes completed for this study includes features mapped to the nominal 30-meter resolution of the input multitemporal elevation datasets. Consequently, spatially explicit change maps have been produced and statistics accumulated for a number of different accounting and reporting units, some broad (states and ecoregions) and some small (quadrangle base maps).

Maps of the location of the individual change polygons are useful for presenting and describing the overall nature of 20th century human geomorphic activity across the conterminous United States. In addition, accumulating summary statistics within various accounting and reporting units helps describe the density of topographic change areas within subdivisions of the landscape with which researchers and resource managers are familiar.

Summary Statistics and Rankings:
States Containing Topographic Change Polygons
Top Ranked Counties (by Area) Containing Topographic Change Polygons
Top Ranked Ecoregions (by Area) Containing Topographic Change Polygons
Top Ranked Watersheds (by Area) Containing Topographic Change Polygons
Top Ranked Managed Areas (by Area) Containing Topographic Change Polygons
Top Ranked Quadrangles (by Percentage) Containing Topographic Change Polygons

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