Calculates distance from a Leaflet Polyline layer.
// Create a Polyline or use an existing one (for example when working with Leaflet.Draw)
var polyline = L.polyline(latlngs).addTo(map);
// Returns the distance in metric units
polyline.measuredDistance();
// Returns the distance in imperial units
polyline.measuredDistance({
metric: false
});Add option for metric or imperial unitsAdd string formatting (eg:1.000 km,1 km,500 m)
Diego Soto https://groups.google.com/forum/#!topic/leaflet-js/I1vQZh4QWjc
Jacob Toye (Leaflet Draw) https://github.com/jacobtoye