The USGS's National Geochemical Survey (NGS) is producing "a body of geochemical data for the United States based primarily on stream sediments, analyzed using a consistent set of methods." After learning the history and background of the project, users can access the NGS data by geographic area. The website allows researchers to compare the analytical methods and view national maps illustrating the distribution of these methods for each element. Visitors can easily view maps of the distribution of arsenic, mercury, lead, calcium, titanium, and other elements.