The Shemya DEM integrates bathymetry and topography in the area surrounding and west of Shemya Island, Alaska, at the westernmost end of the Aleutian Islands. It encompasses the neighboring islands of Attu, Agattu, Nizki, and Alaid (the Semichi Islands). The DEM has a 1 arc-second (~30 meter) cell size, and is referenced to a vertical datum of mean high water. It was built in July 2009 to support NOAA's Tsunami Program.
|Horizontal Datum||WGS 84|
|Vertical Datum||MHW (meters)|
|Vertical Transformation||Source elevation data transformed vertically using a constant offset derived from NOAA tide predictions.|
|Cell Size||1 arc-second|
|Source||NOAA / NGDC / MGG|
|Developer||NOAA / NGDC / MGG|
|Project||NOAA Tsunami Inundation|
|Contact||Barry W Eakins @ NOAA / NGDC|
WARNING: DEM not to be used for navigation.