Trigger warning as approach gps waypoint

My brother purchased a new boat with swing out racks for wakeboards and skis. Now this is a potential issue when trying to drive into the boat lift as the racks need to be retracted. Is is feasible to have the Adriano poll gps coordinates and trigger a warning when within a certain distance of set coordinates? Obviously it will poll switched on the track and trigger an audio warning. Thanks!

Useful formulas for distance and bearing to waypoints are given here: http://www.movable-type.co.uk/scripts/latlong.html

A limitation of the Arduino is that it supports only single-precision floating point calculations. This is not accurate enough for some types of GPS coordinate calculations, but may work well enough in your case.

jremington: Useful formulas for distance and bearing to waypoints are given here: http://www.movable-type.co.uk/scripts/latlong.html

A limitation of the Arduino is that it supports only single-precision floating point calculations. This is not accurate enough for some types of GPS coordinate calculations, but may work well enough in your case.

Ok great thanks! Precision is not top priority. Large zone several hundred feet in diameter would be fine.