Garmin GMI 20 Marine Instrument Quick Start Manual - Page 4

Using the GMI 10 Use the GMI 10 to view numerical data provided by connected sensors. Many data types can also be displayed as an analog gauge (page 6). The types of data available are determined by the sensors connected to the GMI 10 either through NMEA 2000 or NMEA 0183. For example, when connected to a GPS antenna such as a GPS 17x, the GMI 10 can show GPS position, course over ground, speed over ground, average speed, maximum speed obtained, and distance traveled (trip odometer) information.  Viewing Information Instrument screens are organized by category. The categories available are: Surface-speed, heading, odometer (requires a GPS antenna or other sensor that measures speed or heading). Water-depth and temperature (requires a sonar device such as an intelligent transducer). Fuel-level, rate, range, economy (requires a fuel sensor such as the GFS 10). You must also have a sensor that provides speed to use range and economy information. GMI 10 Quick Start Manual