Just click two or more points on the map to measure the geodesic distance between the points. You can drag the vertex markers and the distance will be updated. Click on the markers and confirm delete to remove the vertex, or type in new latitude and longitude values and select Save to update the vertex. The distance units of measure can be set to meters, kilometers or miles. The distance line color can be defined by the user. The distance calculations use the Haversine formula from this site. The measurements can be exported out as KML, WKT or CSV formats; just click Export.