使用百度地图实现地图网格

var ZMap = function (id, center, level) {
    this.initCenter = new ZPoint(116.404, 39.915);//初始化的中心点，同时为了定义网格的中心点
    this.id = id;//div的id
    this.level = level ? level : 13;//地图级别
    this.center = center ? center : this.initCenter;//中心点

    this.map = null;//百度地图实例
    this.xgrids = [];//经线
    this.ygrids = [];//纬线
    this.beSelectBounds = {};
    this.bounds = null;//当前地图的四个顶点
    this.span = null;//当前网格的跨度

    this.init();

}
ZMap.prototype = {
    init: function () {//全局初始化
        var zMap = this;
        this.map = new BMap.Map(this.id);
        this.map.centerAndZoom(this.center.point, this.level);
        this.map.enableScrollWheelZoom();
        this.map.disableInertialDragging();
        this.map.addControl(new BMap.NavigationControl({
            anchor: BMAP_ANCHOR_BOTTOM_RIGHT,
            type: BMAP_NAVIGATION_CONTROL_ZOOM
        })); //缩放按钮
        this.map.addControl(new BMap.ScaleControl({anchor: BMAP_ANCHOR_BOTTOM_LEFT, offset: new BMap.Size(80, 25)})); //比例尺
        this.map.disableDoubleClickZoom();
        this.map.setMapStyle({style: 'googlelite'});
        this.initProperty();
        this.initGrid();

        //添加移动后的点击事件
        this.map.addEventListener("dragend", function () {
            zMap.initProperty();
            zMap.initGrid();
        });
        //添加放大或缩小时的事件
        this.map.addEventListener("zoomend", function () {
            zMap.initProperty();
            zMap.initGrid();
        });
        //设置点击事件
        this.map.addEventListener("click", function (e) {
            var point = e.point;
            //获取当前点是在哪个区块内,获取正方形的四个顶点
            var points = zMap.getGrid(point);

            //判断当前区域是否已经被选中过，如果被选中过则取消选中
            var key = '' + points[0].lng + points[0].lat + points[2].lng + points[2].lat;//使用两个点的坐标作为key
            if (zMap.beSelectBounds[key]) {
                zMap.map.removeOverlay(zMap.beSelectBounds[key]);
                delete zMap.beSelectBounds[key];
                return;
            }
            var polygon = new BMap.Polygon(points, {strokeColor: "red", strokeWeight: 2, strokeOpacity: 0.5});
            zMap.map.addOverlay(polygon);
            zMap.beSelectBounds[key] = polygon;

        });
    },
    initProperty: function () {//初始化当前地图的状态
        this.level = this.map.getZoom();
        this.bounds = {
            x1: this.map.getBounds().getSouthWest().lng,
            y1: this.map.getBounds().getSouthWest().lat,
            x2: this.map.getBounds().getNorthEast().lng,
            y2: this.map.getBounds().getNorthEast().lat
        };
        this.span = this.getSpan();//需要使用level属性
    },
    initGrid: function () {//初始化网格
        var zMap = this;
        //将原来的网格线先去掉
        for (var i in zMap.xgrids) {
            this.map.removeOverlay(zMap.xgrids[i]);
        }
        zMap.xgrids = [];
        for (var i in zMap.ygrids) {
            this.map.removeOverlay(zMap.ygrids[i]);
        }
        zMap.ygrids = [];
        //获取当前网格跨度
        var span = zMap.span;
        //初始化地图上的网格
        for (var i = zMap.bounds.x1 + (zMap.initCenter.point.lng - zMap.bounds.x1) % span.x - span.x; i < zMap.bounds.x2 + span.x; i += span.x) {
            var polyline = new BMap.Polyline([
                new BMap.Point(i.toFixed(6), zMap.bounds.y1),
                new BMap.Point(i.toFixed(6), zMap.bounds.y2)
            ], {strokeColor: "black", strokeWeight: 1, strokeOpacity: 0.5});
            zMap.xgrids.push(polyline);
            zMap.map.addOverlay(polyline);
        }
        for (var i = zMap.bounds.y1 + (zMap.initCenter.point.lat - zMap.bounds.y1) % span.y - span.y; i < zMap.bounds.y2 + span.y; i += span.y) {
            var polyline = new BMap.Polyline([
                new BMap.Point(zMap.bounds.x1, i.toFixed(6)),
                new BMap.Point(zMap.bounds.x2, i.toFixed(6))
            ], {strokeColor: "black", strokeWeight: 1, strokeOpacity: 0.5});
            zMap.ygrids.push(polyline);
            zMap.map.addOverlay(polyline);
        }
    },
    getSpan: function () {//获取网格的跨度
        var scale = 0.75;
        var x = 0.00064;
        for (var i = this.level; i < 19; i++) {
            x *= 2;
        }
        var y = parseFloat((scale * x).toFixed(5));
        return {x: x, y: y};
    },
    getGrid: function (point) {//返回当前点在所在区块的四个顶点
        var zMap = this;
        //先找出两条纵线坐标
        var xpoints = this.xgrids.map(function (polyline) {
            return polyline.getPath()[0].lng;
        }).filter(function (lng) {
            return Math.abs(lng - point.lng) <= zMap.span.x;
        }).sort(function (a, b) {
            return a - b;
        }).slice(0, 2);

        //再找出两条横线的坐标
        var ypoints = this.ygrids.map(function (polyline) {
            return polyline.getPath()[0].lat;
        }).filter(function (lat) {
            return Math.abs(lat - point.lat) <= zMap.span.y;
        }).sort(function (a, b) {
            return a - b;
        }).slice(0, 2);

        return [
            new BMap.Point(xpoints[0], ypoints[0]),
            new BMap.Point(xpoints[0], ypoints[1]),
            new BMap.Point(xpoints[1], ypoints[1]),
            new BMap.Point(xpoints[1], ypoints[0])
        ];

    },
    reset: function () {//重置
        this.map.reset();
    }
}

var ZPoint = function (x, y, code) {
    this.code = code;
    this.point = new BMap.Point(x, y);
}