We combine long-term records from aerial photographs, detailed mapping using survey-grade GPS, and ground-based lidar with meteorological monitoring. Sand dune migration rates are currently about 35 meters per year.
Main page for National Hydrography Dataset (NHD), a comprehensive set of digital spatial data about surface water features, with links to references, data, software tools, applications, tutorials, technical support, and data maintenance.
Portal to general information on the National Atlas of the United States with access for producing specialized maps and links to thematic maps including interactive maps, multimedia maps, map layers data warehouse, wall maps, and printable maps.
Post-earthquake map derived from 1:24,000-scale base maps incorporating high- and medium-resolution remotely sensed imagery following the 7.0 magnitude earthquake near the capital city of Port au Prince, Haiti, on January 12, 2010