Creights - 1 year ago 146
Javascript Question

# Using the Haversine Formula in Javascript

I'm trying to use the Haversine Distance Formula (as found here: http://www.movable-type.co.uk/scripts/latlong.html) but I can't get it to work, please see the following code

function test() {
var lat2 = 42.741;
var lon2 = -71.3161;
var lat1 = 42.806911;
var lon1 = -71.290611;

var R = 6371; // km
//has a problem with the .toRad() method below.
var a = Math.sin(dLat/2) * Math.sin(dLat/2) +
Math.sin(dLon/2) * Math.sin(dLon/2);
var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));
var d = R * c;

}

And the error is:

Uncaught TypeError: Object -0.06591099999999983 has no method 'toRad'

Which I understand to be because it needs to do the following:

return this * Math.PI / 180;
}

But when I put this below the function, it still comes back with the same error message. How do I make it use the helper method? Or is there an alternative way to code this to get it to work? Thanks!

This code is working:

return this * Math.PI / 180;
}

var lat2 = 42.741;
var lon2 = -71.3161;
var lat1 = 42.806911;
var lon1 = -71.290611;

var R = 6371; // km
//has a problem with the .toRad() method below.
var x1 = lat2-lat1;