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<DIV STYLE="text-align:Left;"><DIV><DIV><P><SPAN STYLE="font-size:9pt">The USGS was entrusted with the responsibility for mapping the country in 1879 and has been the primary civilian mapping agency of the United States ever since. The best known USGS maps are the 1:24,000-scale topographic maps, also known as 7.5-minute quadrangles. From approximately 1947 to 1992, more than 55,000 7.5-minute maps were made to cover the 48 conterminous states. Similar maps at varying scales were produced during the same time period for Alaska, Hawaii, and US Territories. The 7.5-minute series was declared complete in 1992, and at that time was the only uniform map series that covered the United States in considerable detail.</SPAN></P><P><SPAN STYLE="font-size:9pt">Map revision continued, though in decreasing quantities, through the 1990s. The last printed USGS topographic maps were published in 2006.</SPAN></P><P><SPAN STYLE="font-size:9pt">In 2009, a new USGS quadrangle topographic map series was defined. Named “US Topo,” these maps are modeled on the 7.5-minute series, but are derived from GIS data. At about the same time, a separate project was started to scan the entire historic library of traditional topographic maps.</SPAN></P><P><SPAN STYLE="font-size:9pt">Today, USGS topographic quadrangle maps are divided into two product types:</SPAN></P><P><SPAN STYLE="font-size:9pt">1. </SPAN><A href="/core-science-systems/national-geospatial-program/us-topo-maps-america?qt-science_support_page_related_con=0"><SPAN STYLE="font-size:9pt">US Topo</SPAN></A><SPAN STYLE="font-size:9pt"> is the current topographic map series. These are modeled on the legacy 7.5-minute maps, but are mass-produced from GIS databases and published as digital documents. </SPAN></P><P><SPAN STYLE="font-size:9pt">2. The </SPAN><A href="/core-science-systems/ngp/topo-maps/historical-topographic-map-collection?qt-science_support_page_related_con=0"><SPAN STYLE="font-size:9pt">Historical Topographic Map Collection (HTMC)</SPAN></A><SPAN STYLE="font-size:9pt">is a set of scanned images of USGS topographic quadrangle maps originally published as paper documents in the period 1884-2006.</SPAN></P><P><SPAN STYLE="font-size:9pt">Both US Topo and HTMC maps can be downloaded free of charge through </SPAN><A href="/faqs/how-do-i-find-and-download-topographic-maps?qt-news_science_products=3"><SPAN STYLE="font-size:9pt">several USGS interfaces</SPAN></A><SPAN STYLE="font-size:9pt">.</SPAN></P><P><SPAN STYLE="font-size:9pt">This dataset is best described by item 2.</SPAN></P><P><SPAN /></P></DIV></DIV></DIV> |
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["Annapolis","Arched Rock","Asti","Big Foot Mountain","Bodega Head","Calistoga","Camp Meeker","Cazadero","Cloverdale","Cotati","Cuttings Wharf","Detert Reservoir","Duncans Mills","Fort Ross","Geyserville","Glen Ellen","Gualala","Gube Mountain","Guerneville","Healdsburg","Jimtown","Kenwood","Mare Island","Mark West Springs","McGuire Ridge","Mount Saint Helena","Novato","Petaluma","Petaluma Point","Petaluma River","Plantation","Plantation OE W","Point Reyes NE","Rutherford","Santa Rosa","Sears Point","Sebastopol","Sonoma","Stewarts Point","Stewarts Point OE W","The Geysers","Tombs Creek","Two Rock","Valley Ford","Warm Springs Dam","Whispering Pines. Sonoma County","USGS","7.5 Minute Quadrangle","Topographic","Contours."] |