ArcGIS API for JavaScriptを使って地図に円の多角形を描きます.

//       ArcGIS API for JavaScript
require([
         "esri/geometry/Circle",
	 "esri/geometry/Polygon",
	 "esri/Map",
	 "esri/layers/GraphicsLayer",
	 "esri/Graphic"

	],function(Circle,Polygon,GraphicsLayer,Map){
	
	var map = new Map("map",{
		center:[-81.3765, 28.54175)],
		slider:false,
		maxZoom: 6,
		fadeOnZoom: true
	});
	var graLayer = new GraphicsLayer();
	
	//    Circle 
	//            
	var symbol = new SimpleFillSymbol().setColor(null).outline.setColor("red");
	
	// lon    lat  （     ） radius   
	function setCircle(lon,lat,radius){
		var pt = new Point(lon,lat,map.spatialReference);
		var radius = radius;
		var circle = new Circle({
			crenter: pt,
			geodesic: true,
			radius: radius
		});
		
		var graphic = new Graphic(circle,symbol);
		graLayer.add(graphic);
	}
	
	//      Polygon
	function setPolygon(){
		var polygon = new Polygon(new SpatialReference({wkid:4326}));
		//              ，  ：     ，    ，             
		polygon.addRing([[-180,-90],[-180,90],[180,90],[180,-90],[-180,-90]]);
		var graphic = new Graphic(circle,symbol);
		graLayer.add(graphic);
	}
	//        
	var tiledMapServiceLayer = new ArcGISTiledMapServiceLayer("http://server.arcgisonline.com/ArcGIS/rest/services/NGS_Topo_US_2D/MapServer");
	map.addLayer(tiledMapServiceLayer);
	map.addLayer(graLayer);
	//    
	map.centerAndZoom(new Point(-81.3765, 28.54175)),6);
});