What is Position Precision ?

Position Precision is a feature that adjusts the number of digits to the right of the decimal places to transmit NMEA output—used in a GPS coordinate sent out by the GPS device over NMEA 0183. The feature allows devices that speak different versions of NMEA 0183 to communicate with each other.

There are different versions of NMEA 0183 (e.g. v1.5, v2, v3.01). These versions of NMEA 0183 will transmit and receive the NMEA 0183 sentence for position differently. Regarding the sending of GPS position, the number of decimal places to define the position has changed between the different NMEA 0183 versions.

Garmin has added this setting that will allow the user to change the amount of decimal places sent out by the GPS. All current GPS devices manufactured by Garmin will output NMEA 0183 version 3.01. Since not all other marine electronics speak this version of NMEA 0183, use the Position Precision to lower the number of decimal places in the GPS NMEA 0183 sentence from the default of 4.