The Bathymetric Shaded Relief of North America map layer shows depth ranges using colors, with relief enhanced by shading. The image was derived from the National Geophysical Data Center's ETOPO2 elevation data, which is an elevation database gridded at 2-minute resolution, containing elevation and bathymetry for the world. The image was produced from the October 2001 data set. This layer is part of the 1997-2014 edition of the National Atlas of the United States. The bathymetric shaded relief image was developed to portray the underwater terrain of North America. The image is intended for visual purposes only. The original ETOPO2 data must be used for conducting analysis and determining specific bathymetric values. National Atlas of the United States. (2005). Bathymetric Shaded Relief of North America. National Atlas of the United States. Available at: http://purl.stanford.edu/nk031bn4014. This image contains color shaded relief in RGB color space. For access to the original 2-byte data, please visit the National Geophysical Data Center web site mentioned below. The associated world file is included as part of the GeoTIFF. The contents of the world file are: >3107.6802 >0.000000 >0.000000 >-3107.6802 >-6084141.6440 >4487139.6139 The following projection file can be used when using ESRI's ArcGIS to view the GeoTIFF (any line breaks should be removed): PROJCS["NAD_1983_Lambert_Azimuthal_Equal_Area",GEOGCS ["GCS_Sphere_ARC_INFO",DATUM["D_Sphere_ARC_INFO",SPHEROID ["Sphere_ARC_INFO",6370997.0,0.0]],PRIMEM["Greenwich",0.0], UNIT["Degree",0.0174532925199433]],PROJECTION ["Lambert_Azimuthal_Equal_Area"],PARAMETER["False_Easting",0.0], PARAMETER["False_Northing",0.0],PARAMETER["Central_Meridian", -100.0],PARAMETER["Latitude_Of_Origin",45.0],UNIT["Meter",1.0]] This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.