Free software for displaying Electronic Nautical Charts (ENC), Raster Nautical Charts (RNC), and Geo-referenced images (IMG) as charts. The program supports the creation and display of Mariner's Cruising Guides (MCG) vector charts, Nautical Chart Image (NCI) tiles, Nautical Chart Overlay (NCO) files, Nautical Chart Vector (NCV) tiles, and Nautical Chart Object/Overlays (NOC) files. The program can also display optional tile based satellite images, waypoint locations and routes. The program can display multiple semi-transparent charts over the tile base images. The program accepts NMEA GPS sentences from most GPS receivers that connect to a USB port. The program also accepts NMEA AIS sentences from most AIS receivers connected to the USB port.