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Examining Our Past: Historical Map Collection Now Online



Examining Our Past: Historical Map Collection Now Online

Nearly 90,000 high resolution scans of the more than 200,000 historical USGS topographic maps, some dating as far back as 1884, are now available online. The Historical Topographic Map Collection includes published U.S. maps of all scales and editions, and are offered as a georeferenced digital download or as a scanned print from the USGS Store.

“I applaud your continuing effort to digitize the entire set of USGS quadrangle maps and we anxiously await the completion of the project. This effort is of great consequence for the research community” said Dr. John R. Hébert Chief, Geography and Map Division, Library of Congress. Not all of the historical collection resides in any one location or in any one catalog. In a partnership with the Library of Congress and other map depositories, the USGS will build a complete master catalog and duplicate maps that may be missing from any of those sources.

Historical maps are an important national resource as they provide the long-term record and documentation of the natural, physical and cultural landscape. The history documented by this collection and the analysis of distribution and spatial patterns is invaluable throughout the sciences and non-science disciplines. Genealogists, historians, anthropologists, archeologists and others use this collection for research as well as for a framework on which a myriad of information can be presented in relation to the landscape. For more than 130 years, the USGS topographic mapping program has accurately portrayed the complex geography of our nation through maps using the lithographic printing process. The historical collection contains high resolution scanned images from the USGS legacy series and other sources.

Historical maps are available to the public at no cost in GeoPDF format or as a printed copy for plus a handling charge from the USGS Store . The electronic maps are georeferenced and can be used in conjunction with the new USGS digital topographic map, the US Topo.

The entire historical collection is being loaded into the USGS Store at a rapid pace. Check the website for continuous updates: http://nationalmap.gov/historical

The project is part of the USGS National Geospatial Program (NGP) continuing efforts to support the mapping and location-based data needs of the Nation. 

USGS Newsroom



More information

Parameter Value Description
Magnitude mb The magnitude for the event.
Longitude ° East Decimal degrees longitude. Negative values for western longitudes.
Latitude ° North Decimal degrees latitude. Negative values for southern latitudes.
Depth km Depth of the event in kilometers.
Place Textual description of named geographic region near to the event. This may be a city name, or a Flinn-Engdahl Region name.
Time 1970-01-01 00:00:00 Time when the event occurred. UTC/GMT
Updated 1970-01-01 00:00:00 Time when the event was most recently updated. UTC/GMT
Timezone offset Timezone offset from UTC in minutes at the event epicenter.
Felt The total number of felt reports
CDI The maximum reported intensity for the event.
MMI The maximum estimated instrumental intensity for the event.
Alert Level The alert level from the PAGER earthquake impact scale. Green, Yellow, Orange or Red.
Review Status Indicates whether the event has been reviewed by a human.
Tsunami This flag is set to "1" for large events in oceanic regions and "0" otherwise. The existence or value of this flag does not indicate if a tsunami actually did or will exist.
SIG A number describing how significant the event is. Larger numbers indicate a more significant event.
Network The ID of a data contributor. Identifies the network considered to be the preferred source of information for this event.
Sources A comma-separated list of network contributors.
Number of Stations Used The total number of Number of seismic stations which reported P- and S-arrival times for this earthquake.
Horizontal Distance Horizontal distance from the epicenter to the nearest station (in degrees).
Root Mean Square sec The root-mean-square (RMS) travel time residual, in sec, using all weights.
Azimuthal Gap The largest azimuthal gap between azimuthally adjacent stations (in degrees).
Magnitude Type The method or algorithm used to calculate the preferred magnitude for the event.
Event Type Type of seismic event.
Event ID Id of event.
Event Code An identifying code assigned by, and unique from, the corresponding source for the event.
Event IDS A comma-separated list of event ids that are associated to an event.

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