The Alaska Mapping Initiative supports acquisition of new topographic map data and generation of updated maps for Alaska. The new data and maps raise the accuracy of Alaska topographic mapping to levels commonly found in the conterminous United States.
New Elevation Data Available Statewide for Alaska
In 2011 the Alaska Congressional Delegation requested federal support to modernize Alaska map data. Collection of a 5-meter resolution elevation grid for Alaska began in 2012, replacing the former 60-meter statewide elevation grid. Radar technology called IfSAR (Interferometric Synthetic Aperture Radar) was used to collect the data because it can penetrate the clouds, smoke, and haze often present in Alaska. Statewide airborne IfSAR collection was completed in 2020 and all data are now processed and available for download. The data are free to the public for any use. Alaska IfSAR acquisition supports the broader national 3D Elevation Program.
Status of Alaska IfSAR Elevation Acquisition
A New Digital US Topo Map Series Is Available Statewide for Alaska
'US Topo' is a digital topographic map format produced by USGS. 11,278 new US Topo maps of Alaska were published by USGS from 2013 to 2021 and provide statewide map coverage at 1:25,000 map scale. Each map is created using new contours generated from the new IfSAR elevation data. The maps are distributed for free download and use in a convenient PDF format that can be viewed on a computer or mobile device, or printed to paper. A second round of new US Topo map generation will begin in summer 2022.
Downloading Alaska IfSAR Data
Two convenient online portals are available for downloading Alaska IfSAR data. The State of Alaska offers 5-meter IfSAR by tiles for the entire State through their elevation portal found at https://elevation.alaska.gov/. USGS offers the 5-meter IfSAR data tiles, and also provides seamless post-processed elevation data at approximately 10-meter, 30-meter, and 60-meter post spacing. Coverage is currently available for all of Alaska except Kodiak Island and the western Aleutian Islands, which are expected to be available by May 2021. These data can be found at https://viewer.nationalmap.gov/basic/. Bulk download is also available from USGS, and instructions can be found at https://viewer.nationalmap.gov/uget-instructions/index.html.
Downloading US Topo Maps
Alaska US Topo maps are available for free download at https://viewer.nationalmap.gov/basic/. Paper copies can be ordered for a fee from the USGS store located online at https://store.usgs.gov/map-locator.
Terrestrial Hydrography Updates
USGS is supporting a statewide update of terrestrial hydrography data (surface water, such as lakes and rivers) for Alaska. The National Hydrography Dataset (NHD), the Watershed Boundary Dataset (WBD), and NHDPlus High Resolution (NHDPlus HR) for Alaska are being updated through collaborative Federal and State partnerships to meet accuracy and content specifications suitable for 1:24,000-scale mapping. Hydrographic features and watershed boundaries are being derived from the Alaska IfSAR elevation data using elevation-derived-hydrography methodology. Revised NHD and WBD data are then used to create important watershed characteristic data delivered via NHDPlus HR. These efforts will eventually support the development of an operational National Water Model for Alaska. The Cook Inlet, Matanuska-Susitna (Mat-Su), and Copper River watersheds are updated through NHDPlus HR. NHD and WBD editing is ongoing for an additional 100,000 square miles in Alaska, primarily on the North Slope. The statewide hydrography update is scheduled for completion in 2030.
