how to add update Google Map option in asp.net application

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ASP.NET

In my application i have to create route for marathon and for that i have to keep option for creating and updating the route on map.All the logic should be inside application only ?
please help me how do i start to work?
In application i have to draw the line by drag and draw feature.

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

var map = new google.maps.Map(document.getElementById('googleMap'),
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);


In above code there is no option to update or reset or edit map.How i can add these functionality in this code?