The Shaded Relief layer is a statewide grayscale hillshade created from the most current 1/3 arc second USGS NED data. The actual resolution of the hillshade is 9.3 meters, which is an average of the 1/3 arc second resolution of the USGS source data.

The NED data for all of Pennsylvania was aquired from USGS and projected from Geographic to Albers NAD 83. The projected data was mosaiced and hillshaded to produce the Shaded Relief Layer. The quality of the hillshade may vary due to variations in the source data used to produce the original NED data.

The Shaded Relief layer can be used as a background layer in SoilMap, or combined with the Aerial Photo and Topo Map layers to produce a 3D effect on these layers. To add a 3D effect to these layers, just turn on the Shaded Relief layer with either the Topo Maps layer or the Aerial Photo layer. When the Shaded Relief and either Topo Maps or Aerial Photos are turned on, the Shaded Relief will shade the other raster layer and create a 3D relief effect. When Shaded Relief is turned on with the other raster layers turned off, it will show as a grayscale shaded relief background.

The National Elevation Dataset (NED) is a new raster product assembled by the U.S. Geological Survey. NED is designed to provide National elevation data in a seamless form with a consistent datum, elevation unit, and projection. Data corrections were made in the NED assembly process to minimize artifacts, perform edge matching, and fill sliver areas of missing data. NED data sources have a variety of elevation units, horizontal datums, and map projections. In the NED assembly process the elevation values are converted to decimal meters as a consistent unit of measure, NAD83 is consistently used as horizontal datum, and all the data are recast in a geographic projection. Older DEM's produced by methods that are now obsolete have been filtered during the NED assembly process to minimize artifacts that are commonly found in data produced by these methods. Artifact removal greatly improves the quality of the slope, shaded-relief, and synthetic drainage information that can be derived from the elevation data.

For More Information - Visit the USGS NED site

The data and documentation on SoilMap are provided 'as is' and the User assumes the entire risk as to their quality and performance. SoilMap source data was produced at a variety of scales and may not be suitable for use at larger scales.