Alaska Statewide Digital Elevation Model Efforts

Alaska’s existing Digital Elevation Models (DEM) are of uneven quality. Many areas have significant accuracy problems, not meeting even DTED-2 standards (LE90 < 18-meters). The National Elevation Database (NED) for Alaska is mostly a 1-arcsecond product (~30 × 60-m post spacing product) created by digitizing contour maps generated from often poorly controlled 1950’s air photography.

2010 collection

157,000 square-kilometers of airborne IfSAR data were flown summer of 2010 and will be delivered with 22-foot contour equivalent accuracy (3-meter LE90) and five meter post spacings. An additional ~200,000 square-kilometers of restrictively licensed IfSAR-derived DEM data will be uplifted into the public domain through this contract.

Dewberry is the prime contractor for the $6 million project being administered by the USGS through their GPSC vehicle. Fugro Earthdata and Intermap have each flown and processed half of the 2010 acquisitions. Major funding contributors include the National Geospatial-Intelligence Agency (NGA), State of Alaska, and USGS. Supporting contributors include the Natural Resources Conservation Service (NRCS), Bureau of Land Management (BLM), and National Park Service.

Shapefiles of the 2010 collection

The future

Additional funds are being sought to complete DEM mapping of the entire state to an accuracy that supports user requirements. Users are encouraged to assist SDMI in planning of DEM collection priorities by providing input to the 2011 survey .