openlayers 应用Google图层你必须做的

    //全局变量
var map,EPSG4326,EPSG900913,lineFeature_map,vectorLayer_map,markers_map;
function init(){
var lonLat= new OpenLayers.LonLat( 121.123, 38.9);
//很重要因为谷歌用得图层投影不一样，所以要统一图层 全要转成该种投影
var XY = lonLat.clone().transform( EPSG4326, EPSG900913 );

   var options = {
                controls: [],
                maxResolution: "auto",
                projection: EPSG900913,
               // displayProjection: EPSG4326,
                munZoomLevels: 5,
                units: "m",
                maxExtent: new OpenLayers.Bounds(-20037508, -20037508,
                                                 20037508,20037508.34)
            };
//加载地图
            map= new OpenLayers.Map('trackInfoMap', options);
            var gphy = new OpenLayers.Layer.Google(
                "Google Physical",
                { type: G_PHYSICAL_MAP ,numZoomLevels: 20,'sphericalMercator':true,}
            );
            var gmap = new OpenLayers.Layer.Google(
                "Google Streets", // the default
                {numZoomLevels: 20 ,'sphericalMercator':true,}
            );
            var ghyb = new OpenLayers.Layer.Google(
                "Google Hybrid",
                { type: G_HYBRID_MAP, numZoomLevels: 20 ,'sphericalMercator':true,}
            );
            var gsat = new OpenLayers.Layer.Google(
                "Google Satellite",
                { type: G_SATELLITE_MAP, numZoomLevels: 20,'sphericalMercator':true, }
            );
vectorLayer_map = new OpenLayers.Layer.Vector("Vector Layer",
{ styleMap: new OpenLayers.StyleMap(featureStyle) });
markers_map = new OpenLayers.Layer.Markers("marker");
map.addLayer(vectorLayer_map);
map.addLayer(markers_map);
var style_green = {
                strokeColor: "#339933",
                strokeOpacity: 1,
                strokeWidth: 3,
                pointRadius: 6,
                pointerEvents: "visiblePainted"
            };
          
            lineFeature_map = new OpenLayers.Feature.Vector(
            new OpenLayers.Geometry.LineString(XY.lon, XY.lat), null, style_green);
           vectorLayer_map.addFeatures([lineFeature_map]);
//添加图层
           map.addLayers([gmap,gphy ,ghyb ,gsat ]);
//设置中心点坐标及放大倍数
           map.setCenter(XY,9);
           fn_Line();
//移除下边的logo 看着有使用说明啥的 确实不舒服
            $("div").remove(".olLayerGoogleCopyright");
            $("div").remove(".olLayerGooglePoweredBy&gmnoprint");
//其实还有很多东西没写  第一写博客 ，也是第一次用这个写，写着很不舒服 ，因为我也//不会弄.还有好多的 控制条啥的  要根据自己需要自己加吧，就写到这吧。opanlayers 确实很强大
   }
//画图函数
function fn_Line() {
var px,py;
       if (x < 20) {
         px = Math.random() * (122 - 121 + 0.001) + 121;
         py = Math.random() * (30 - 29 + 0.001) + 38;
         var lonLat = new OpenLayers.LonLat(px, py);
         var lonLat_ = lonLat.clone().transform(EPSG4326, EPSG900913);
         var p1_ = new OpenLayers.Geometry.Point(lonLat_lon, lonLat_lat);
//划线
         lineFeature_map.geometry.addPoint(p1_);
         vectorLayer_map.drawFeature(lineFeature_map);
//加标记
          markers_map.clearMarkers();
          var marker = new OpenLayers.Marker(lonLat_);
          markers_map.addMarker(marker);
                x++;
                setTimeout(fn, 1000);
            }
        }