How to calculate distance between five markers?

Question

How do you calculate the distance between five markers in Google maps V3? I know I have to use Haversine formula which I researched and even found a post in here teaching on calculating the distance between two markers. What if I want to calculate it between five markers ? Been trying for a few hours but the km calculated is so wrong. Thanks

Following codes are below:

// compute distance between the two points
    var R = 6371; // KM
    var dLat = toRad(location5.lat()-location4.lat()-location3.lat()-location2.lat()-location1.lat());
    var dLon = toRad(location5.lng()-location4.lng()-location3.lng()-location2.lng()-location1.lng()); 

    var dLat1 = toRad(location1.lat());
    var dLat2 = toRad(location2.lat());
    var dLat3 = toRad(location3.lat());
    var dLat4 = toRad(location4.lat());
    var dLat5 = toRad(location5.lat());

    var a = Math.sin(dLat/2) * Math.sin(dLat/2) +
            Math.cos(dLat1) * Math.cos(dLat1) * 
            Math.sin(dLon/2) * Math.sin(dLon/2); 
    var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a)); 
    var d = R * c;

    document.getElementById("distance_direct").innerHTML = "<br/><br/><br/>The distance between the five points (in a straight line) is: "+d +" Km.";
}

function toRad(deg) 
{
    return deg * Math.PI/180;
}

I guess my wrong part is with the line starting with var a formula. Please indicate my error if im wrong and maybe a solution to help?

Answer 1

The computeLength() function in google maps V3 should give you what you need, see http://code.google.com/intl/el/apis/maps/documentation/javascript/geometry.html#Distance

Answer 2

The function you are using is for the distance between two coordinates. You need to calculate the distance from A->B then B->C and then add those distances up at the end.

var distAB = calcDist(location1,location2);
var distBC = calcDist(location2,location3);
var distCD = calcDist(location3,location4);
var distDE = calcDist(location4,location5);

var distTotal = distAB + distBC + distCD + distDE;

function calcDist(locationA,locationB)
{
    var R = 6371; // KM
    var dLat = toRad(locationB.lat()) - toRad(locationA.lat());
    var dLng = toRad(locationB.lng()) - toRad(locationA.lng());
    var a = Math.sin(dLat/2) * Math.sin(dLat/2) +
        Math.cos(dLat1) * Math.cos(dLat1) * 
        Math.sin(dLon/2) * Math.sin(dLon/2); 
    var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a)); 
    return R * c;
}

function toRad(deg) 
{
    return deg * Math.PI/180;
}