测量地图面积

1：先在页面上弄一个div，给它设置样式，并且给它点击事件mapMeasurementArea ()，创建矢量图层：
markerLayer = new SuperMap.Layer.Markers(“Markers”)；
把创建的矢量图层添加到Map地图里面：
map.addLayers(markerLayer);
然后创建画面控制：
drawPolygon = new SuperMap.Control.DrawFeature(polygonLayer, SuperMap.Handler.Polygon);
drawPolygon.events.on({ “featureadded”: drawCompletedDrawPolygon });
2:写击事件，每次点击的时候都要清除上一次的查询，然后开始绘制方框：
function mapMeasurementArea() {
clearFeatures();
drawPolygon.activate();
drawLine.deactivate();
}
3：写量算画面数据获取：
function drawCompletedDrawPolygon(drawGeometryArgs) {
drawPolygon.deactivate();
var geometry = drawGeometryArgs.feature.geometry,
measureParam = new SuperMap.REST.MeasureParameters(geometry)，
myMeasuerService = new SuperMap.REST.MeasureService(url);
myMeasuerService.events.on({ “processCompleted”: measureCompleted1, “processFailed”: processFailed111 });
myMeasuerService.measureMode = SuperMap.REST.MeasureMode.AREA;

        myMeasuerService.processAsync(measureParam); 
    }

4：获取上一步查询到的数据，然后将数据用弹窗显示出来，
function measureCompleted1(measureEventArgs) {

        var area = measureEventArgs.result.area,
                unit = measureEventArgs.result.unit;
        Laylayer.open({
            shade: 0,
            content: "量算结果：" + area + "米",
            zIndex: 0,
            offset: 't',
            yes: function (index, layero) {
                Laylayer.close(index);
                clearFeatures();
            },
            cancel: function (index, layero) {
                Laylayer.close(index);
                clearFeatures();
            }
        })
    }

5：看看效果：