我对使用 Google map 以及 MySQL 数据库中存储的地理位置/坐标有疑问。
代码示例:
<html>
<head>
<meta name="viewport" content="initial-scale=1.0, user-scalable=no"/>
<meta http-equiv="content-type" content="text/html; charset=UTF-8"/>
<title>TRACKING MARKERS</title>
<style>
html{height:100%;}
body{height:50%; width:50%;margin:0px;font-family: Helvetica,Arial;}
</style>
<script src="https://maps.googleapis.com/maps/api/js?key=MY-API-KEY&callback=initMap"></script>
<script type ="text/javascript" src="http://www.geocodezip.com/scripts/v3_epoly.js"></script>
<script type="text/javascript">
var map;
var directionDisplay;
var directionsService;
var stepDisplay;
var position;
var marker = [];
var polyline = [];
var poly2 = [];
var poly = null;
var startLocation = [];
var endLocation = [];
var timerHandle = [];
var speed = 5, wait = 1;
var infowindow = null;
var myPano;
var panoClient;
var nextPanoId;
var startLoc = new Array();
startLoc[0] = 'Berlin, Germany';
startLoc[1] = 'Berlin, Germany';
startLoc[2] = 'Berlin, Germany';
startLoc[3] = 'Berlin, Germany';
var endLoc = new Array();
endLoc[0] = 'Zagreb, Croatia';
endLoc[1] = 'Zagreb, Croatia';
endLoc[2] = 'Zagreb, Croatia';
endLoc[3] = 'Zagreb, Croatia';
var Colors = ["#FF0000", "#00FF00", "#0000FF"];
function initialize() {
infowindow = new google.maps.InfoWindow(
{
size: new google.maps.Size(150,50)
});
var myOptions = {
zoom: 16,
mapTypeId: google.maps.MapTypeId.ROADMAP
}
map = new google.maps.Map(document.getElementById("map_canvas"), myOptions);
address = 'Sarajevo, Bosnia and Herzegovina'
geocoder = new google.maps.Geocoder();
geocoder.geocode( { 'address': address}, function(results, status) {
map.fitBounds(results[0].geometry.viewport);
});
// setRoutes();
}
function createMarker(latlng, label, html) {
// alert("createMarker("+latlng+","+label+","+html+","+color+")");
var contentString = '<b>'+label+'</b><br>'+html;
var marker = new google.maps.Marker({
position: latlng,
map: map,
title: label,
zIndex: Math.round(latlng.lat()*-100000)<<5
});
marker.myname = label;
google.maps.event.addListener(marker, 'click', function() {
infowindow.setContent(contentString);
infowindow.open(map,marker);
});
return marker;
}
function setRoutes(){
var directionsDisplay = new Array();
for (var i=0; i< startLoc.length; i++){
var rendererOptions = {
map: map,
suppressMarkers : true,
preserveViewport: true
}
directionsService = new google.maps.DirectionsService();
var travelMode = google.maps.DirectionsTravelMode.DRIVING;
var request = {
origin: startLoc[i],
destination: endLoc[i],
travelMode: travelMode
};
directionsService.route(request,makeRouteCallback(i,directionsDisplay[i]));
}
function makeRouteCallback(routeNum,disp){
if (polyline[routeNum] && (polyline[routeNum].getMap() != null)) {
startAnimation(routeNum);
return;
}
return function(response, status){
if (status == google.maps.DirectionsStatus.OK){
var bounds = new google.maps.LatLngBounds();
var route = response.routes[0];
startLocation[routeNum] = new Object();
endLocation[routeNum] = new Object();
polyline[routeNum] = new google.maps.Polyline({
path: [],
strokeColor: '#FFFF00',
strokeWeight: 3
});
poly2[routeNum] = new google.maps.Polyline({
path: [],
strokeColor: '#FFFF00',
strokeWeight: 3
});
// For each route, display summary information.
var path = response.routes[0].overview_path;
var legs = response.routes[0].legs;
disp = new google.maps.DirectionsRenderer(rendererOptions);
disp.setMap(map);
disp.setDirections(response);
//Markers
for (i=0;i<legs.length;i++) {
if (i == 0) {
startLocation[routeNum].latlng = legs[i].start_location;
startLocation[routeNum].address = legs[i].start_address;
// marker = google.maps.Marker({map:map,position: startLocation.latlng});
marker[routeNum] = createMarker(legs[i].start_location,"start",legs[i].start_address,"green");
}
endLocation[routeNum].latlng = legs[i].end_location;
endLocation[routeNum].address = legs[i].end_address;
var steps = legs[i].steps;
for (j=0;j<steps.length;j++) {
var nextSegment = steps[j].path;
var nextSegment = steps[j].path;
for (k=0;k<nextSegment.length;k++) {
polyline[routeNum].getPath().push(nextSegment[k]);
//bounds.extend(nextSegment[k]);
}
}
}
}
polyline[routeNum].setMap(map);
//map.fitBounds(bounds);
startAnimation(routeNum);
} // else alert("Directions request failed: "+status);
}
}
var lastVertex = 1;
var stepnum=0;
var step = 50; // 5; // metres
var tick = 100; // milliseconds
var eol= [];
//----------------------------------------------------------------------
function updatePoly(i,d) {
// Spawn a new polyline every 20 vertices, because updating a 100-vertex poly is too slow
if (poly2[i].getPath().getLength() > 20) {
poly2[i]=new google.maps.Polyline([polyline[i].getPath().getAt(lastVertex-1)]);
// map.addOverlay(poly2)
}
if (polyline[i].GetIndexAtDistance(d) < lastVertex+2) {
if (poly2[i].getPath().getLength()>1) {
poly2[i].getPath().removeAt(poly2[i].getPath().getLength()-1)
}
poly2[i].getPath().insertAt(poly2[i].getPath().getLength(),polyline[i].GetPointAtDistance(d));
} else {
poly2[i].getPath().insertAt(poly2[i].getPath().getLength(),endLocation[i].latlng);
}
}
//----------------------------------------------------------------------------
function animate(index,d) {
if (d>eol[index]) {
marker[index].setPosition(endLocation[index].latlng);
return;
}
var p = polyline[index].GetPointAtDistance(d);
//map.panTo(p);
marker[index].setPosition(p);
updatePoly(index,d);
timerHandle[index] = setTimeout("animate("+index+","+(d+step)+")", tick);
}
//-------------------------------------------------------------------------
function startAnimation(index) {
if (timerHandle[index]) clearTimeout(timerHandle[index]);
eol[index]=polyline[index].Distance();
map.setCenter(polyline[index].getPath().getAt(0));
poly2[index] = new google.maps.Polyline({path: [polyline[index].getPath().getAt(0)], strokeColor:"#FFFF00", strokeWeight:3});
timerHandle[index] = setTimeout("animate("+index+",50)",2000); // Allow time for the initial map display
}
//----------------------------------------------------------------------------
</script>
</head>
<body onload="initialize()">
<div id="tools">
<button onclick="setRoutes();">Start</button>
</div>
<div id="map_canvas" style="width:100%;height:100%;"></div>
</body>
</html>
代码的这个特定部分是我的问题:
var startLoc = new Array();
startLoc[0] = 'Berlin, Germany';
startLoc[1] = 'Berlin, Germany';
startLoc[2] = 'Berlin, Germany';
startLoc[3] = 'Berlin, Germany';
var endLoc = new Array();
endLoc[0] = 'Zagreb, Croatia';
endLoc[1] = 'Zagreb, Croatia';
endLoc[2] = 'Zagreb, Croatia';
endLoc[3] = 'Zagreb, Croatia';
假设 Loc0、loc1、loc2 和 loc3 是火车组合的一部分 - 机车和 3 节车厢；他们每个人都有一个跟踪设备，可以在数据库中发送地理位置。
我可以吗？如果可以的话 - 有人知道如何 - 使用数据库中的数据而不是上面示例中的硬编码地理位置吗？
最佳答案
您可以从数据库中检索这些地理位置记录，并借助 PHP、Jsp 等 Web 脚本语言将它们放入 json 字符串中。
然后，您的 javascript 获取这些数据并使用它们(Ajax 应该更好)
关于javascript - 如何根据 MySQL 数据库中存储的坐标显示动画多个标记，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/39302476/