C-MAP 4D Electronic Marine Charts are the next evolution in navigation solutions. C-MAP 4D adapts to your boating needs because it’s the only digital chart that offers advanced features and lets you add data and services as they become available.C-MAP 4D cartography is compatible with the Furuno 1670F / 1870F, and Standard CPN 7000i, and CPN1010i units. C-MAP 4D NA-D933 Lake Erie and Lake St Clair Coverage: Coverage of Lake Erie and Lake St Clair. More Features and Specifications