RealtimeMap.vue: update heading calculation logic, use the heading to two...

      }

      this.update_location()

    },

    calculateBusAngle(lat1, lon1, lat2, lon2) {

      const dLon = (lon2 - lon1);

      const y = Math.sin(dLon) * Math.cos(lat2);

      const x = Math.cos(lat1) * Math.sin(lat2) - Math.sin(lat1)

          * Math.cos(lat2) * Math.cos(dLon);

    calculateBusAngle(startLat, startLng, destLat, destLng) {

      // 将度数转换为弧度

      function toRadians(degrees) {

        return degrees * Math.PI / 180;

      };

      let brng = Math.atan2(y, x);

      // 将弧度转换为度数

      function toDegrees(radians) {

        return radians * 180 / Math.PI;

      }

      brng = brng * (180 / Math.PI);

      brng = (brng + 360) % 360;

      brng = 360 - brng; // 如果需要顺时针度数，请移除此行

      // 转换起始点和目标点的经纬度为弧度

      startLat = toRadians(startLat);

      startLng = toRadians(startLng);

      destLat = toRadians(destLat);

      destLng = toRadians(destLng);

      return brng;

      // 计算方位角

      const y = Math.sin(destLng - startLng) * Math.cos(destLat);

      const x = Math.cos(startLat) * Math.sin(destLat) - Math.sin(startLat) * Math.cos(destLat) * Math.cos(destLng - startLng);

      let brng = Math.atan2(y, x);

      brng = toDegrees(brng);

      return (brng + 360) % 360;

    },

    findNearestPointOnSegment(point, segmentStart, segmentEnd) {

      const A = point[0] - segmentStart[0];

      return [xx, yy];

    },

    findNearestSegment(busLocation, geojsonLine) {

      let closestSegment = [geojsonLine[0], geojsonLine[1]];

      let closestSegmentStart = geojsonLine[0];

      let closestSegmentEnd = geojsonLine[1];

      let minDistance = Number.MAX_VALUE;

      // 遍历 GeoJSON 线路的每个线段

      for (let i = 0; i < geojsonLine.length - 1; i++) {

        const point1 = geojsonLine[i];

        const point2 = geojsonLine[i + 1];

        const distance = this.calculateDistance(busLocation, this.findNearestPointOnSegment(busLocation, point1, point2));

        const segmentStart = geojsonLine[i];

        const segmentEnd = geojsonLine[i + 1];

        const nearestPoint = this.findNearestPointOnSegment(busLocation, segmentStart, segmentEnd);

        const distance = this.calculateDistance(busLocation, nearestPoint);

        // 更新最近线段

        if (distance < minDistance) {

          minDistance = distance;

          closestSegment = [point1, point2];

          closestSegmentStart = segmentStart;

          closestSegmentEnd = segmentEnd;

        }

      }

      return closestSegment;

      // 确保线段的顺序与 GeoJSON 中的一致

      return [closestSegmentStart, closestSegmentEnd];

    },

    calculateDistance(point1, point2) {

      return Math.sqrt(Math.pow(point2[0] - point1[0], 2) + Math.pow(point2[1] - point1[1], 2));

        // if current time - report time < 300s, then display

        if (parseInt(new Date().getTime() / 1000) - this.bus_location_data_api[i].time_mt < 300) {

          const busLocation = [this.bus_location_data_api[i].lng, this.bus_location_data_api[i].lat];

          var busHeadingAngle = 0

          if (this.bus_location_data_api[i].route_code.slice(-1) === '1') { //XYBS1

            this.bus_location_data_api[i].route_geojson = this.geojson_line_1

            const closestSegment = this.findNearestSegment(busLocation, this.bus_location_data_api[i].route_geojson);

            console.log(closestSegment)

            busHeadingAngle = this.calculateBusAngle(closestSegment[0][1], closestSegment[0][0], closestSegment[1][1], closestSegment[1][0]);

          } else { //XYBS2

            this.bus_location_data_api[i].route_geojson = this.geojson_line_2

          }

            const closestSegment = this.findNearestSegment(busLocation, this.bus_location_data_api[i].route_geojson);

          const busHeadingAngle = this.calculateBusAngle(busLocation[1], busLocation[0], closestSegment[1][1], closestSegment[1][0]);

            busHeadingAngle = this.calculateBusAngle(closestSegment[0][1], closestSegment[0][0], closestSegment[1][1], closestSegment[1][0]) - 180;

          }

          // create a DOM element for the marker