public static int velocityUnitStringToIndex(String unit) {
       switch (unit) {
            case "kph":
                return 0;
            case "mph":
                return 1;
            case "m/s": 
                return 2;
            case "kn":
                return 3;
            case "kts":
                return 4;
            default:
                return 0;
        } 
    }