Ваше поле инициализации карты в onCreate
map = mapboxMap;
mapboxMap.addPolygon(generatePerimeter(new LatLng(trackLat, trackLong), 0.200, 64));
Ваш метод
private PolygonOptions generatePerimeter(LatLng centerCoordinates, double radiusInKilometers, int numberOfSides) {
List<LatLng> positions = new ArrayList<>();
return new PolygonOptions()
.addAll(positions)
.fillColor(Color.GREEN)
.strokeColor(Color.YELLOW)
.alpha(1f);
}