由于百度地图搜索结果仅能显示单条公交线路，不利于对公交线网的研究，于是我写了这个基于百度地图JavaScript API V3.0的公交线路绘制网站（http://www.84ditu.com）。本文主要介绍绘制公交的基础功能，其中部分代码涉及jQuery。

成品图

申请API密钥

首先要有一个百度账号，并且申请成为百度开发者，然后才能申请ak，应用类型选择浏览器端，必须勾选JavaScript API，最后将申请到的ak作为script链接的一部分在html中的head部分引入。

ak申请

生成地图并自动定位

var map = new BMap.Map("map"); //"map"为用于展示地图的div的id
var city;
var myCity = new BMap.LocalCity();
myCity.get(getCity);
function getCity (res) {
  if (res) {
    city = res.name;
    map.centerAndZoom(city, 13);
  } else {
    city = "温州市"; //默认城市
  }
}

判断路线是否已添加

function addLine (line) {
  if ($.inArray(line, readyAdd) == -1) {
    bus.getBusList(line);
    readyAdd.push(line); //readyAdd为空数组，用于存储已添加的线路名
  } else {
    alert("该路线已添加");
  }
}

检索并生成路线

var getPolylineOptions = function getPolylineOptions () { //线路样式配置
  return {
    strokeColor: $("#strokeColor").val(),
    strokeWeight: $("#strokeWeight").val(),
    strokeOpacity: $("#strokeOpacity").val(),
    strokeStyle: $("#strokeStyle").val()
  }
};
var bus = new BMap.BusLineSearch(map, {
  onGetBusListComplete: function onGetBusListComplete (result) {
    let busListItem = $("#busListItem").val(); //公交上下行
    let fstLine = result.getBusListItem(busListItem);
    bus.getBusLine(fstLine);
  },
  onGetBusLineComplete: function onGetBusLineComplete (busline) {
    polyline = new BMap.Polyline(busline.getPath(), getPolylineOptions());
    let lineName = busline.name.substr(0, busline.name.indexOf("(")); //提取线路名
    map.addOverlay(polyline); //添加折线覆盖物
    let stationList = []; //获取站点
    for (let i = 0, len = busline.getNumBusStations(); i < len; i++) {
      let busStation = busline.getBusStation(i);
      let marker = new BMap.Marker(busStation.position, {
        icon: stationIcon
      });
      stationList.push(new BMap.Point(busStation.position.lng, busStation.position.lat));
      if ($("#strokeStation").val() == "true") { //显示站点
        map.addOverlay(marker);
        marker.setTitle(lineName + ":" + busStation.name);
        marker.addEventListener("click", function (e) { //单击站点显示信息
          let opts = {
            width: 250,
            height: 80,
            title: e.target.getTitle().substr(e.target.getTitle().indexOf(":") + 1)
          };
          let content = busline.name;
          let infoWindow = new BMap.InfoWindow(content, opts);
          let point = new BMap.Point(e.target.getPosition().lng, e.target.getPosition().lat);
          map.openInfoWindow(infoWindow, point);
        });
      }
    }
    if (enableAutoViewport) {
      let view = map.getViewport(eval(stationList));
      map.centerAndZoom(view.center, view.zoom);
    }
    polyline.addEventListener("dblclick", function (e) { //双击线路删除路径
      let allOverlay = map.getOverlays();
      for (let i = 0, len = allOverlay.length; i < len; i++) {
        if (allOverlay[i].toString() == "[object Marker]") {
          if (allOverlay[i].getTitle().substr(0, allOverlay[i].getTitle().indexOf(":")) == lineName) {
            allOverlay[i].enableMassClear();
          } else {
            allOverlay[i].disableMassClear();
          }
        } else {
          allOverlay[i].disableMassClear();
        }
      }
      e.target.enableMassClear();
      map.clearOverlays();
      let index = readyAdd.indexOf(lineName);
      readyAdd.splice(index, 1);
    });
    polyline.addEventListener("mouseover", function (e) { //移向线路高亮路径
      if (e.target == currentPolyline) {
        return false;
      }
      currentPolyline = e.target;
      lineOpacity = currentPolyline.getStrokeOpacity();
      currentPolyline.setStrokeOpacity("1");
    });
    polyline.addEventListener("mouseout", function (e) {
      e.target.setStrokeOpacity(lineOpacity);
    })
  }
});