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.
Elevation data used in the map were retrieved from the Shutter Radar Topography Mission (SRTM-DEM; [42]), that is publicly available at no charge, a courtesy of the U.S. Geological Survey.
