I just want to know if there is a way to notify the user if there is a marker in like.. 100 meters in front of them, and I mean in front the bearing/degree of the user.
just like:
Or if there is a way to attach a triangle polygon's top point to the bearing/degree of the user?
PS: I'm creating an app to reduce traffic.
You could use the Mapbox Java SDK port of http://turfjs.org/docs/#bearing
https://github.com/mapbox/mapbox-java/blob/master/docs/turf-port.md#measurement