Commonly Asked Questions

How were these county DEMs produced?

The following procedure was used to produce a county or city DEM:

What is the resolution of the DEMs?

The county DEMs are created from USGS 7.5' DEMs. Each elevation cell represents either 10 meters or 30 meters, depending on the availability of the newer USGS 10 meter product. Elevation units are in meters. Any USGS DEMs that originally had elevations in feet have been converted to meters.

How often will Radford University update these files?

Since the USGS continually updates its DEM products, we will reproduce the data sets in their entirety annually. Look for new files next November. Please note that many county data sets will remain the same, since the USGS only updates some files each year.