Openlayers3实现车辆轨迹回放功能

记录基于geoserver地图服务，Openlayers3在web前端实现车辆轨迹回放功能，并记录和解决过程中出现的linestring只描绘部分经纬度坐标问题。

参考Openlayers3 官网例子

html

 
 
 
 
 
 



 
 

 

 

 
 

 

 

 

 

  

  
轨迹查询
  
  
 
 

  

  

  设备

  

  
   请选择设备
  
  
  
  


  

  

  日期

  

  

   
   
  
  
  
  

  

   轨迹查询 
  
 
  

   轨迹回放 
   速度
 
 
 
 

map初始化

$(document).ready(function () {
 map = new ol.Map({
 logo: false,
 target: document.getElementById('map'),
 layers: layers,
 view: view
 });
 initSelect();//设备下拉框列表初始化
 //时间控件初始化
 $('#s-traceday').val(transfromTime(new Date(),false)+" 00:00:00");
 $('#e-traceday').val(transfromTime(new Date(),true));
 $('.datepicker').datetimepicker({
 minView:0,
 format: 'yyyy-MM-dd hh:mm:ss', 
 todayBtn : "linked", 
 autoclose : true, 
 todayHighlight : true,
 startDate: daylimit,
 endDate:'+1d'//结束时间，在这时间之后都不可选
 });
});

//轨迹line layer
var vsource = new ol.source.Vector({
 type: 'LineString',
 features: []
});
var linelayers = new ol.layer.Vector({
 source: vsource,
 style: new ol.style.Style({
 fill: new ol.style.Fill({
 color: '#0044CC'
 }),
 stroke: new ol.style.Stroke({
 color: '#0044CC',
 width: 4
 })
 })
});
//地图基础参数
var map;
var center = [121.6606763113213, 31.14611063632111];
var lng, lat;
var source = new ol.source.Vector({
 wrapX: false
});;
var projection = new ol.proj.Projection({
 code: 'EPSG:4326',
 units: 'degrees',
 axisOrientation: 'neu'
});
var view = new ol.View({
 projection: projection,
 center: center,
 zoom: 16
});

var layers = [new ol.layer.Tile({
 title: '、地图',
 visible: true,
 preload: Infinity,
 source: new ol.source.TileWMS({
 url: gisUrl,
 params: {
 'VERSION': '1.1.0',
 tiled: true,
 STYLES: '',
 LAYERS: 'shanghai:maptest',
 }
 })
 }),linelayers];

ajax获取坐标数据

//轨迹查询按钮点击
var positions=[];
$("#queryBtn").click(function(){
 //清除之前的图层
 if (centerSource.getFeatures != null) {
 centerSource.clear(); }
 linelayers.getSource().clear(true);
 positions=[];//清空
 //取值
 var busnum=$("#busSelect").val();
 var traceday=$("#traceday").val();
 if(busnum=="*"){
 $(".remind").html('请先选择车辆');
 return;
 }else{
 $(".remind").html('');
 busnum=busnum.slice(2);
 }
 if(transfromTime(new Date(),false)==traceday){//当天
 traceday="*";
 }else{
 traceday=traceday.replace(/(-)/g,"");
 }
 $(".remind").html(' 正在查询...');

 //请求
 $.getJSON(baseUrl+"trace/query/"+busnum+"/"+traceday,"",function(data){
 if(data.length==0){
 $(".remind").html('未查到gps数据');return;
 }
 var position = [];
 for(var i = 0;i该车辆当天停在该位置未启动');
 centerAt(positions[0]);
 return;
 }
 AddLayer(positions);
 });
});

显示轨迹

//轨迹描绘
function AddLayer() {
 var lineFeature = new ol.Feature({//路线
 geometry: new ol.geom.LineString(positions,'XY'),
 });
 linelayers.getSource().addFeature(lineFeature);

 var startFeature = new ol.Feature({//起点
 geometry: new ol.geom.Point(positions[0]),
 population: 4000,
 rainfall: 500
 });
 startFeature.setStyle(startStyle);
 linelayers.getSource().addFeature(startFeature);
 var endFeature = new ol.Feature({//终点
 geometry: new ol.geom.Point(positions[positions.length-1]),
 population: 4000,
 rainfall: 500
 });
 endFeature.setStyle(endStyle);
 linelayers.getSource().addFeature(endFeature);


 carFeature = new ol.Feature({//车子
 geometry: new ol.geom.Point(positions[0]),
 population: 4000,
 rainfall: 500
 });
 carFeature.setStyle(carStyle);
 linelayers.getSource().addFeature(carFeature);
 var extent = linelayers.getSource().getExtent();//合适比例缩放居中
 view.fit(extent, map.getSize());
 }

显示单点

//居中 车辆不运动时居中显示图标处理
var centerLayer = null;
var centerSource = new ol.source.Vector({
 features: null
});
//居中在一个位置
function centerAt(position) {
 var pan = ol.animation.pan({
 duration: 2000,
 source: (view.getCenter())
 });
 view.setCenter(position);

 var iconFeature = new ol.Feature({
 geometry: new ol.geom.Point(position),
 name: 'Null Island',
 population: 4000,
 rainfall: 500
 });
 iconFeature.setStyle(iconStyle);
 centerSource.addFeature(iconFeature);
 centerLayer = new ol.layer.Vector({
 source: centerSource
 });
 map.addLayer(centerLayer);
 centerLayer.setVisible(true);
}

点在线上运动，轨迹回放

//轨迹回放start 参考官网
var carFeature = null;
var speed, now;
var animating = false;
$("#animateBtn").click(function(){
 if(positions.length==0){
 $(".remind").html('请先查询轨迹');
 return;
 }
 if (animating) {
 stopAnimation(false);
 } else {
 animating = true;
 now = new Date().getTime();
 speed = $("#speed").val();//速度
 $("#animateBtn").html(' 取消回放');
 carFeature.setStyle(null);
 // map.getView().setCenter(center);
 map.on('postcompose', moveFeature);
 map.render();
 }
});

var moveFeature = function(event) {
 var vectorContext = event.vectorContext;
 var frameState = event.frameState;

 if (animating) {
 var elapsedTime = frameState.time - now;
 // here the trick to increase speed is to jump some indexes
 // on lineString coordinates
 var index = Math.round(speed * elapsedTime / 1000);

 if (index >= positions.length) {
 stopAnimation(true);
 return;
 }

 var currentPoint = new ol.geom.Point(positions[index]);
 var feature = new ol.Feature(currentPoint);
 vectorContext.drawFeature(feature, carStyle);
 }
 // tell OL3 to continue the postcompose animation
 map.render();
 };

 function startAnimation() {
 if (animating) {
 stopAnimation(false);
 } else {
 animating = true;
 now = new Date().getTime();
 speed = speedInput.value;
 $("#animateBtn").html(' 取消回放');
 // hide geoMarker
 geoMarker.setStyle(null);
 // just in case you pan somewhere else
 map.getView().setCenter(center);
 map.on('postcompose', moveFeature);
 map.render();
 }
 }

 function stopAnimation(ended) {
 animating = false;
 $("#animateBtn").html(' 轨迹回放');

 // if animation cancelled set the marker at the beginning
 var coord = ended ? positions[positions.length - 1] : positions[0];
 /** @type {ol.geom.Point} */ (carFeature.getGeometry())
 .setCoordinates(coord);
 //remove listener
 map.un('postcompose', moveFeature);
 }
//轨迹回放end

解决linestring坐标显示不全

期间碰到一个问题

var lineFeature = new ol.Feature({//路线
 geometry: new ol.geom.LineString(positions,'XY'),
 });
 linelayers.getSource().addFeature(lineFeature);

调用这段代码显示轨迹时，从数据库取到20个坐标，就可能只显示4个坐标，本来是弯曲的轨迹，但是实际上就是折线，很尴尬。
误打误撞，和同学 交流过程中发现问题所在，特此感谢。
在ajax获取坐标数据中发现问题所在：
原先错误代码

position = [data[i].lon,data[i].lat];
 positions.push(position);

正确代码

position = [parseFloat(data[i].lon),parseFloat(data[i].lat)];
 positions.push(position);

原因就是没有把float类型的坐标利用parseFloat强转，导致默认的泛数据类型精确度不够，经纬度小数点后末尾几位就会被忽略，于是造成数据失效，描出的线就会有问题。

附上icon、起点、终点、车辆等地图样式

//样式，供上述代码调用
var iconStyle = new ol.style.Style({
 image: new ol.style.Icon(/** @type {olx.style.IconOptions} */ ({
 anchor: [0.5, 0.8],
 anchorXUnits: 'fraction',
 anchorYUnits: 'pixels',
 opacity: 0.75,
 src: 'img/iconfont-weizhi-red.png'
 }))
});
var startStyle = new ol.style.Style({
 image: new ol.style.Icon(/** @type {olx.style.IconOptions} */ ({
 anchor: [0.5, 0.8],
 opacity: 0.8,
 src: 'img/start.png'
 /*anchorXUnits: 'fraction',
 anchorYUnits: 'pixels',
 opacity: 0.75,*/

 }))
});
var endStyle = new ol.style.Style({
 image: new ol.style.Icon(/** @type {olx.style.IconOptions} */ ({
 src: 'img/end.png',
 anchor: [0.5, 0.8],
 }))
});
var carStyle = new ol.style.Style({
 image: new ol.style.Icon(/** @type {olx.style.IconOptions} */ ({
 src: 'img/car.png',
 anchor: [0.5, 0.8],
 }))
});

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。