I'm trying to find the location between two points using google maps. Here is the code that I'm working with:

function initialize() {

          var myOptions = {

            center: new google.maps.LatLng(36.8813329,-103.6975488),

            zoom: 4,

            mapTypeId: google.maps.MapTypeId.ROADMAP

          };

          var map = new google.maps.Map(document.getElementById(map-canvas), myOptions);



           var impactCoordinates = [

              new google.maps.LatLng(37.772323, -122.214897),

              new google.maps.LatLng(34.1633766,-81.6487862),

                             ];

            var ImpactPath = new google.maps.Polyline({

              path: impactCoordinates,

              strokeColor: #FF0000,

              strokeOpacity: 1.0,

              strokeWeight: 2

            });



            ImpactPath.setMap(map);



            var loc1 = new google.maps.LatLng(37.772323, -122.214897);

            var loc2 = new google.maps.LatLng(34.1633766,-81.6487862);



            alert(google.maps.geometry.spherical.computeDistanceBetween(loc1, loc2));

        }

This is the error I get from the console:

Uncaught TypeError: Cannot read property 'spherical' of undefined