Detailed coverage of the Gulf of Mexico from Brownsville, TX to Plantation Key, FL including Corpus Christi, TX, Matagorda Bay, Galveston Bay, Port Arthur, TX, Atchafalaya Bay, the Mississippi Delta, Chandeleur Islands, Tampa Bay and the Florida Keys west of Key Largo. Also includes Lake Ponchartrain and Lake Maurepas to Vermilion Bay and Lake Calcasieu. Bathymetric coverage of offshore features from Vernon Basin to Alaminos Canyon including DeSoto Canyon, Mississippi Canyon and Green Canyon.