How to get lat/lang/radius of center of circle that user draw

Question

I'm using this exmaple from https://developers.google.com/maps/documentation/javascript/examples/drawing-tools to enable user to choose a point and enable user to draw a circle around it.

However, I need also to:

• get the lat/lang of center of circle that user draw.
• get the radius of circle.

• also the code allows user to draw more than one circle, if possible, I need to restrict user to draw only one circle, if user draw another circle, first circle should be removed.

  
  function initialize() {
    var mapOptions = {
      center: new google.maps.LatLng(-34.397, 150.644),
      zoom: 8
    };
  
  var map = new google.maps.Map(document.getElementById('map-canvas'),
      mapOptions);
  
  var drawingManager = new google.maps.drawing.DrawingManager({
      drawingMode: google.maps.drawing.OverlayType.MARKER,
      drawingControl: true,
      drawingControlOptions: {
        position: google.maps.ControlPosition.TOP_CENTER,
        drawingModes: [
          google.maps.drawing.OverlayType.MARKER,
          google.maps.drawing.OverlayType.CIRCLE,
          google.maps.drawing.OverlayType.POLYGON,
          google.maps.drawing.OverlayType.POLYLINE,
          google.maps.drawing.OverlayType.RECTANGLE
        ]
      },
      markerOptions: {
        icon: 'images/beachflag.png'
      },
      circleOptions: {
        fillColor: '#ffff00',
        fillOpacity: 1,
        strokeWeight: 5,
        clickable: false,
        editable: true,
        zIndex: 1
      }
    });
    drawingManager.setMap(map);
  }
  
  google.maps.event.addDomListener(window, 'load', initialize);
  

Answer 1

See http://jsfiddle.net/stevejansen/2HpA6

(function () {
    var circle;

    function initialize() {
        var mapOptions = {
            center: new google.maps.LatLng(-34.397, 150.644),
            zoom: 8
        };


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

        var drawingManager = new google.maps.drawing.DrawingManager({
            drawingMode: google.maps.drawing.OverlayType.MARKER,
            drawingControl: true,
            drawingControlOptions: {
                position: google.maps.ControlPosition.TOP_CENTER,
                drawingModes: [
                google.maps.drawing.OverlayType.CIRCLE]
            },
            circleOptions: {
                fillColor: '#ffff00',
                fillOpacity: 1,
                strokeWeight: 5,
                clickable: false,
                editable: true,
                zIndex: 1
            }
        });
        drawingManager.setMap(map);
        google.maps.event.addListener(drawingManager, 'circlecomplete', onCircleComplete);
    }

    function onCircleComplete(shape) {
        if (shape == null || (!(shape instanceof google.maps.Circle))) return;

        if (circle != null) {
            circle.setMap(null);
            circle = null;
        }

        circle = shape;
        console.log('radius', circle.getRadius());
        console.log('lat', circle.getCenter().lat());
        console.log('lng', circle.getCenter().lng());
    }

    google.maps.event.addDomListener(window, 'load', initialize);
})();