The USGS is coordinating a 3D Elevation Program (3DEP) effort with other Federal agency partners and the State of Alaska to acquire new statewide Alaska elevation data. Under its Geospatial Products and Services Contract (GPSC), the USGS is contracting with vendors to acquire 5-meter resolution elevation data using Interferometric Synthetic Aperture Radar (InSAR) sensors flown on aircraft. The data products derived from this effort include a Digital Terrain Model (DTM) representing the bare earth, a Digital Surface Model (DSM) representing the tops of vegetation and structures, and an orthorectified radar intensity image (ORI). These new data replace decades-old 60-meter resolution elevation data that have known vertical and horizontal errors. With the 2019 acquisition of Kodiak, St. Lawrence, St. Matthew, St. Paul, St. George, Chirikof, Middleton, and the western Aleutian Islands, complete statewide InSAR coverage has been achieved. The USGS plans to have all Alaska InSAR data processed and published by the end of 2020.
InSAR data are being used in a wide variety of mapping, resource management, and human safety applications. The new elevation data serve as a foundational layer for new USGS digital topographic maps that are being generated statewide for Alaska. InSAR is also being used to update and refine the digital water-surface layer for Alaska that is critical to many applications. These Alaska mapping efforts are coordinated through the Alaska Mapping Executive Committee (AMEC), an executive body co-chaired by the Department of the Interior and the Department of Commerce. AMEC members represent multiple Federal agencies and the State. Alaska InSAR elevation data can be downloaded through the USGS The National Map data download service at https://viewer.nationalmap.gov/basic.
InSAR hillshade depiction of the Mendenhall Glacier terminus, AK.