摘要：原文來自百度地圖根據已知坐標畫點線，這兩天用到的，在這里做個筆記，方便自己查閱開啟鼠標滾輪縮放添加比例尺控件生成坐標點畫線配置圖片畫圖標創建標注根據經緯極值計算綻放級別。從網上復制沒有坐標，顯示全中國

原文來自 taoeer.top

百度地圖根據已知坐標畫點線，這兩天用到的，在這里做個筆記，方便自己查閱！

var map = new BMap.Map("map");
    var point = new BMap.Point(116.404, 39.915);
    map.centerAndZoom(point, 15);
    map.enableScrollWheelZoom(); // 開啟鼠標滾輪縮放
    map.addControl(new BMap.ScaleControl()); // 添加比例尺控件

    var pointStr = "104.038748,30.641821,104.047789,30.648128,104.063959,30.655336,104.067264,30.660307,104.067264,30.664438,104.064008,30.665316".split(",");
    var pointArr = [];
    
    for (var k = 0; k < pointStr.length; k += 2) {
        pointArr.push({
            lng: pointStr[k],
            lat: pointStr[k + 1]
        });
    }
    
    // 生成坐標點
    var trackPoint = [];
    for (var i = 0, j = pointArr.length; i < j; i++) {
        trackPoint.push(new BMap.Point(pointArr[i].lng, pointArr[i].lat));
    }

    map.centerAndZoom(trackPoint[0], 15);
    
    // 畫線
    var polyline = new BMap.Polyline(trackPoint, {
        strokeColor: "#1869AD",
        strokeWeight: 3,
        strokeOpacity: 1
    });
    map.addOverlay(polyline);
       
    // 配置圖片
    var size = new BMap.Size(26, 26);
    var offset = new BMap.Size(0, -13);
    var imageSize = new BMap.Size(26, 26);
    var icon = new BMap.Icon("./express-position.png", size, {
        imageSize: imageSize
    });
    
    // 畫圖標
    for (var i = 0, j = trackPoint.length; i < j; i++) {
        var marker = new BMap.Marker(trackPoint[i], {
            icon: icon,
            offset: offset
        }); // 創建標注    
        map.addOverlay(marker);

    }

    //根據經緯極值計算綻放級別。 (從網上復制)
    function getZoom(maxLng, minLng, maxLat, minLat) {
        var zoom = ["50", "100", "200", "500", "1000", "2000", "5000", "10000", "20000", "25000", "50000", "100000", "200000", "500000", "1000000", "2000000"]; // 級別18到3。
        var pointA = new BMap.Point(maxLng, maxLat); // 創建點坐標A
        var pointB = new BMap.Point(minLng, minLat); // 創建點坐標B
        var distance = map.getDistance(pointA, pointB).toFixed(1); //獲取兩點距離,保留小數點后兩位
        for (var i = 0, zoomLen = zoom.length; i < zoomLen; i++) {
            if (zoom[i] - distance > 0) {
                return 18 - i + 3; //之所以會多3，是因為地圖范圍常常是比例尺距離的10倍以上。所以級別會增加3。
            }
        }
    }
    
    //  (從網上復制)
    function setZoom(points) {
        if (points.length > 0) {
            var maxLng = points[0].lng;
            var minLng = points[0].lng;
            var maxLat = points[0].lat;
            var minLat = points[0].lat;
            var res;
            for (var i = points.length - 1; i >= 0; i--) {
                res = points[i];
                if (res.lng > maxLng) maxLng = res.lng;
                if (res.lng < minLng) minLng = res.lng;
                if (res.lat > maxLat) maxLat = res.lat;
                if (res.lat < minLat) minLat = res.lat;
            }
            var cenLng = (parseFloat(maxLng) + parseFloat(minLng)) / 2;
            var cenLat = (parseFloat(maxLat) + parseFloat(minLat)) / 2;
            var zoom = getZoom(maxLng, minLng, maxLat, minLat);
            map.centerAndZoom(new BMap.Point(cenLng, cenLat), zoom);
        } else {
            //沒有坐標，顯示全中國
            map.centerAndZoom(new BMap.Point(103.388611, 35.563611), 5);
        }
    }

    setZoom(pointArr)