Removing polygon from google maps drawingManager V3

Question

I have a user editable google map where users can draw an overlay polygon onto the map using the drawing manager. This works fine and the console logs the lat lngs I need. However, I need to add a button that will clear the map of the polygon so they can draw again if a mistake was made. My implementation code is pasted below:

geocoder = new google.maps.Geocoder();
      var latlng = new google.maps.LatLng(<?php echo $latitude ?>, <?php echo $longitude ?>);
       var myOptions = {
         zoom: <?php echo $zoomlevel ?>,
         center: latlng,
         mapTypeId: google.maps.MapTypeId.ROADMAP
       };
       var map = new google.maps.Map(document.getElementById("map_canvas"), myOptions);

       marker = new google.maps.Marker({
         map:map,
         draggable:true,
         animation: google.maps.Animation.DROP,
         position: latlng
       })

       pos = marker.position;
       //alert(pos);
       document.getElementById("gpsite-surgery-latitude").value = pos.lat();
       document.getElementById("gpsite-surgery-longitude").value = pos.lng();

       google.maps.event.addListener(marker, "dragend", function() {
               var myLatLng = marker.latLng;

               pos = marker.position;
               //alert(pos);
               document.getElementById("gpsite-surgery-latitude").value = pos.lat();
               document.getElementById("gpsite-surgery-longitude").value = pos.lng();
       })

       google.maps.event.addListener(map, 'zoom_changed', function() {
          document.getElementById("gpsite-surgery-zoomlevel").value = map.getZoom();
       });

       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.POLYGON]
        },
        polygonOptions: {
            fillColor: '#ffff00',
            fillOpacity: 0.4,
            strokeWeight: 3,
            clickable: true,
            zIndex: 1,
            editable: false
        }
       });


       google.maps.event.addListener(drawingManager, 'polygoncomplete', function (polygon) {
            var coordinates = (polygon.getPath().getArray());
            console.log(coordinates);
        });

       drawingManager.setMap(map);

   });

There is also a marker on the map, you can ignore this.

Answer 1

Examine this code, it sounds exactly like what you are talking about, a button to delete the shape

http://gmaps-samples-v3.googlecode.com/svn-history/r282/trunk/drawing/drawing-tools.html

Edit: above link is broken but I was able to find that code here.

  // globals
  var drawingManager;
  var selectedShape;

  ...

  function clearSelection() {
    if (selectedShape) {
      selectedShape.setEditable(false);
      selectedShape = null;
    }
  }

  function setSelection(shape) {
    clearSelection();
    selectedShape = shape;
    shape.setEditable(true);
    selectColor(shape.get('fillColor') || shape.get('strokeColor'));
  }

  function deleteSelectedShape() {
    if (selectedShape) {
      selectedShape.setMap(null);
    }
  }

     google.maps.event.addListener(drawingManager, 'overlaycomplete', function(e) {
        if (e.type != google.maps.drawing.OverlayType.MARKER) {
        // Switch back to non-drawing mode after drawing a shape.
        drawingManager.setDrawingMode(null);

        // Add an event listener that selects the newly-drawn shape when the user
        // mouses down on it.
        var newShape = e.overlay;
        newShape.type = e.type;
        google.maps.event.addListener(newShape, 'click', function() {
          setSelection(newShape);
        });
        setSelection(newShape);
      }
    });

    // Clear the current selection when the drawing mode is changed, or when the
    // map is clicked.
    google.maps.event.addListener(drawingManager, 'drawingmode_changed', clearSelection);
    google.maps.event.addListener(map, 'click', clearSelection);
    google.maps.event.addDomListener(document.getElementById('delete-button'), 'click', deleteSelectedShape);

    buildColorPalette();
  }

Answer 2

You need a reference to the polygon in the global context. Then in the click handler function for the button call polygon.setMap(null) (where polygon is a global reference to the polygon, can't tell if it is global or not from the incomplete snippet you posted)