The Velocity application turns Fitbit Ionic into a smart digital compass and a speedometer using the data taken from the onboard GPS receiver. It can be used as a backup navigation solution while hiking or walking, and it is an invaluable tool for a small sailboat that helps you understand how well the sails are trimmed and keep to the desired course.

- Shows the current and maximum speed (tap to switch between units).

- Indicates acceleration/slowdown with a color bar.

- Shows the rotating analog compass directed to the average heading (tap to switch between current/average heading).

- Lock mode to lock the average heading and increase compass resolution (down button to enable/disable)

- Calculates time to sunset/sunrise (time screen, click up button to switch between screens).

An application is free. User manual: https://gaperton.github.io/velocity/