 = L.map('leaf_map', {
                //地图渲染在canvas上
                preferCanvas: true,
                //不添加属性说明控件
                attributionControl: false,
                //添加缩放控件
                zoomControl: true,
                //投影坐标系
                crs: L.CRS.EPSG4326,
                //中心点
                center: [(29.0125822276524 + 33.2932017737021) / 2, (108.34341 + 116.150939561213)
                / 2],
                //最大级�