This raster layer is a100-meter resolution land and water mask in (GeoTIFF format) of the conterminous Alaska, with separate values for oceans and for land areas of the United States, Canada, Mexico, the Bahamas, and Cuba. This layer is part of the 1997-2014 edition of the National Atlas of the United States. This 100-meter resolution mask image is not intended to be shown as a map layer. Instead, it is a cartographic tool that may be used to identify, select, and adjust areas on other 100-meter resolution image data sets distributed by the National Atlas of the United States. None. Acknowledgment of The National Atlas of the United States of America would be appreciated in products derived from these data. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.