The color of the target shows the type of area it is on:
- Red (a raspberry red, like the buttons of the app): OK, on open sea.
- Dark blue: on land.
- Green: within 1 pixel of the shoreline (*).
- Yellow: in an exclusion zone.
- Pale bluish white: within the ice limit (AEZ).

(*) Read in this FAQ “Anti-grounding safety pixel: what does it mean?”
To go further: Zones.