// 海量point生成器
function generatePointArr (log, lat, index, obj) {
    log = parseFloat(log);
    lat = parseFloat(lat);
    var mpt = new BMap.Point(log, lat);
    var massFeature = new BMap.MassFeature(mpt, {
        data: obj,
        icon: new BMap.Icon("/etc/designs/gtja/mobile/themes/images/map_maker.png", new BMap.Size(50,78))
    });
    pointArr.push(massFeature);
}
// 添加覆盖物，以第一个点为中心点
function addMarker() {
    branchMap.panTo(pointArr[0].point);
    branchMap.addMassFeatures(pointArr);
}
// 清除覆盖物
function removeMarker() {
    branchMap.removeMassFeatures(pointArr);
    pointArr = []; // 看此处
}