How to obtain the distance between two Location objects

RE: How to obtain the distance between two Location objects

MarkusGL — Mon, 04 Apr 2016 09:54:47 GMT

Thank you very much.
This is a good starting point :)

RE: How to obtain the distance between two Location objects

jim_m_58 — Fri, 01 Apr 2016 17:04:17 GMT

Yes, the thread Travis linked to provides both methods. I've been using the "planetscooter" method since then, but I changed it some parameter wise and this is it now:

//

	// distance between two location (meters) and returns formatted string

	//

	function computeDistance(lat1, lon1, lat2, lon2) {

		var mlat,mlon;

		var dx, dy, distance;

    

  		mlat = (lat1 + lat2) / 2 * 0.01745;

  		dx = 111.3 * Math.cos(mlat) * (lon1 - lon2); 

  		dy = 111.3 * (lat1 - lat2);

  		distance = 1000 * Math.sqrt(dx * dx + dy * dy);

  		return distToStr(distance);

	}

it isn't exact for short distances (<300'), and some of that is the GPS locations can be a bit off, just by the nature of GPS. "distToStr()" converts the meters into a string of meters or feet, km or miles, based on the watch's setting for "distanceUnits".

RE: How to obtain the distance between two Location objects

travis.vitek — Fri, 01 Apr 2016 15:04:43 GMT

If you know you're only going to deal with points that are relatively close, you can use the pythagorean theorem. If you are potentially showing the distance between points very far away, you should consider using the haversine. This post has examples of both bits of code.