var start_stop_btn,
    wpid = false,
    map,
    z,
    op,
    prev_lat,
    prev_long,
    min_speed = 0,
    max_speed = 0,
    min_altitude = 0,
    max_altitude = 0,
    distance_travelled = 0,
    min_accuracy = 150,
    date_pos_updated = "",
    info_string = "";
function format_time_component(time_component)
{
    if (time_component < 10)
        time_component = "0" + time_component;
    else if (time_component.length < 2)
        time_component = time_component + "0";
    return time_component;
}
function geo_success(position)
{
    info_string = "";
    var d = new Date();
    var h = d.getHours();
    var m = d.getMinutes();
    var s = d.getSeconds();
    var current_datetime = format_time_component(h) + ":" + format_time_component(m) + ":" + format_time_component(s);
    if (position.coords.accuracy <= min_accuracy)
    {
        if (prev_lat != position.coords.latitude || prev_long != position.coords.longitude)
        {
            if (position.coords.speed > max_speed)
                max_speed = position.coords.speed;
            else if (position.coords.speed < min_speed)
                min_speed = position.coords.speed;
            if (position.coords.altitude > max_altitude)
                max_altitude = position.coords.altitude;
            else if (position.coords.altitude < min_altitude)
                min_altitude = position.coords.altitude;
            prev_lat = position.coords.latitude;
            prev_long = position.coords.longitude;
            info_string = "Current positon: lat=" + position.coords.latitude + ", long=" + position.coords.longitude + " (accuracy " + Math.round(position.coords.accuracy, 1) + "m)" + (min_speed ? "<br />Speed: min=" + min_speed + "m/s, max=" + max_speed + "m/s" : "") + (min_altitude ? "<br />Altitude: min=" + min_altitude + "m, max=" + max_altitude + "m (accuracy " + Math.round(position.coords.altitudeAccuracy, 1) + "m)" : "") + "<br />last reading taken at: " + current_datetime;
        }
    }
    else
        info_string = "Accuracy not sufficient (" + Math.round(position.coords.accuracy, 1) + "m vs " + min_accuracy + "m) - last reading taken at: " + current_datetime;
    if (info_string)
        op.innerHTML = info_string;
}
function geo_error(error)
{
    switch (error.code)
    {
    case error.TIMEOUT:
        op.innerHTML = "Timeout!";
        break;
    }
    ;
}
function get_pos()
{
    if (!!navigator.geolocation)
        wpid = navigator.geolocation.watchPosition(geo_success, geo_error, {
            enableHighAccuracy: true,
            maximumAge: 30000,
            timeout: 27000
        });
    else
        op.innerHTML = "ERROR: Your Browser doesnt support the Geo Location API";
}
function init_geo()
{
    op = document.getElementById("output");
    if (op)
    {
    	navigator.geolocation.clearWatch(wpid);
    	wpid = false;
    	get_pos();
    }
}
window.onload = init_geo;