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Mapping the Final Frontier

Mapping the Final Frontier

USGS releases more than 400 updated US Topo maps of Alaska

More than 400 new topographic maps are now available for the state of Alaska. The new maps are part of the U.S. Geological Survey Alaska Mapping Initiative, to update foundational data for the state and to replace the existing maps that are about 50 years old.

“These new digital maps of Alaska are elevating our visual record of the surface of the state to 21st century levels,” said Anne Castle, Assistant Secretary of the Interior for Water and Science.  “The associated advances in human safety, navigation, and natural resource management cannot be overestimated. The productive partnership between the State government and the USGS is facilitating acquisition of the necessary data to complete digital mapping of Alaska, which is a critical chapter in the history of our geographical knowledge of the North American continent.”

The first 400-plus new US Topo maps for Alaska are now accessible and are the beginning of a multi-year project, ultimately leading to more than 11,000 new maps for the entire state. The goal of the AMI is the production of a complete series of digital topographical maps at a scale of 1:25,000 to replace the 1:63,360-scale maps produced about 50 years ago. The maps will be published in digital PDF format (GeoPDF©) and are available for free download and manipulation on a computer.

These new maps include several layers, with an option for the user to turn them on or off. Major updated features include:

  • Satellite image layers which allows a recent view of the earth’s surface.
  • Contours and shaded relief layers showing the lay of the land derived from newly acquired 5-meter radar elevation data.
  • Surface water features from the USGS National Hydrography Dataset, which are updated by local stewards and USGS.
  • Glaciers updated using Randolph Glacier Inventory data.
  • Boundaries integrated from multiple sources, including Census and major Federal landholders.
  • The Public Land Survey System layer from the Bureau of Land Management.
  • Roads from a commercial vendor under a USGS contract.
  • Railroads and the Trans-Alaska oil pipeline data from local sources.
  • Important buildings including police stations, schools, and hospitals.
  • Airports, heliports and seaplane landing strips compiled by USGS from multiple sources.
  • Feature names from the USGS-maintained Geographic Names Information System.

To ensure that the maps meet current accuracy specifications and standards, the maps will be made using newly acquired elevation and imagery data from multiple state, federal and commercial sources. The map-making process will be largely automated using software specially adapted by the USGS to create approximately 11,275 digital map quadrangles, covering the entire area of the state.

Mapping in Alaska did not keep pace with records for the rest of the nation as a result of difficult terrain, remote locations, and vast distances. Modern mapping information does not exist over the majority of land in the state. Prior to this effort, topographical maps for much of Alaska were about 50 years out of date and not produced to current standards, which rely largely on high resolution digital imagery and elevation data. As a consequence, essential public services have suffered, among them transportation planning and safety, urban and regional planning, economic development, natural resource management, conservation and scientific research.

This new generation of digital topographic maps will continue the rich and valuable USGS cartographic history, and serve the Nation by providing reliable scientific information to describe and understand the Earth; minimize loss of life and property from natural disasters; manage water, biological, energy, and mineral resources; and enhance and protect quality of life.

For more information and download, go to:

caption below caption below
Historically, Alaska has been a proving ground for many developments in modern surveying and mapping. Field surveying and topographical mapping of the Alaskan interior by the USGS began in the 1890s following the discovery of gold in the Yukon. Travel was often by dog sled and pack train, canoe and walrus-skin kayak as shown in this undated photo. (Larger image) Part of a new US Topo quadrangle map of Fairbanks, Alaska – southwest borough with enhanced elevation contours, surface water, names, transportation, and structures data. (Larger image, 25 MB)

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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