to the National Atlas Home page
About | Fact Sheets | Contact Us | Partners | Products | Site Map | FAQ | Help | Follow us on Twitter 
Part of Project LogoAgricultureBiologyBoundariesClimateEnvironmentGeologyGovernmentHistoryMappingPeopleTransportationWater
to the Interactive Map MakerMap LayersPrintable MapsWall MapsDynamic MapsArticlesMapping Professionals
 
 

Map Layer Info

     
 
Grayscale United States Shaded Relief – 200 Meter Resolution

What this map layer shows:

The shape of the land surface of the United States, in gray and at a resolution of 200 meters.

Also available is Grayscale North America Shaded Relief – 1 Kilometer Resolution

opens the U.S. Geological Survey home page
Background Information
Sample map Sample Map
The National Elevation Dataset (NED) is a raster product assembled by the U.S. Geological Survey (USGS), designed to provide national elevation data in a seamless form with a consistent datum, elevation unit, and projection. Each grid cell in the national elevation model has a value that represents the average height above sea level within that cell. Data corrections made in the NED assembly process minimize artifacts, permit edge matching, and fill sliver areas of missing data. Elevation data are an essential part of many earth science applications. They are used for such diverse purposes as providing shaded-relief backgrounds, establishing stratification in land cover classification, doing geometric and radiometric correction of remotely sensed data, and determining landform characteristics such as slope and aspect. The Grayscale United States Shaded Relief – 200 Meter Resolution map layer was derived from NED data and was produced by the Center for Earth Resources Observation and Science (EROS) of the USGS. EROS archives, processes, and distributes remotely sensed data, including elevation data at various scales, and works with agencies and organizations around the world to support studies using remotely sensed data.

The three-dimensional appearance of the map layer was achieved by determining a gray tone at each point, calculated from the steepness of the slope combined with illumination as if there were a light source in the northwest. The height is exaggerated ten times. The exaggeration factor applied to elevation data in the calculation of shaded relief is necessary to add depth so that features can be seen clearly, but it can be misleading. For example, stream valleys can look like steep canyons. In general, grayscale shaded relief can make flat-to-moderate landscapes appear more rugged than they really are.

The Grayscale United States Shaded Relief – 200 Meter Resolution map layer is four shaded-relief images showing the terrain of the conterminous United States, Alaska, Hawaii, and Puerto Rico and the U.S. Virgin Islands. A separate image was created for each of the four areas of the United States because, at 200 meter resolution, file size for an elevation mosaic of all of the United States would exceed the processing capacity of some commonly-used GIS and image processing software packages. The images show the general nature of the landscape in a visually dramatic way. Grayscale shaded relief does not portray elevation values. There is no way to tell from grayscale shaded relief how high or low an area is and precise measurements of slope or aspect cannot be made. The original NED data must be used for conducting analysis and determining elevation values.

The Grayscale United States Shaded Relief – 200 Meter Resolution map layer is available in both a Lambert Azimuthal Equal-Area projection and an Albers Conical Equal-Area projection. Only the Lambert files can be viewed with the National Atlas Map Maker.

 

Geology
Map Maker Sample
Shaded Relief Land – Gray