计算给定时间的地理位置 [英] Calculate the geo position at given time
本文介绍了计算给定时间的地理位置的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
使用 Google API指示我可以将所有信息从一个地方移到另一个地方，我也可以完成所有步骤。
但是我不知道在给定时间之后是否有方法检索/计算位置（Lat / Lng）。假设，为了简化，我的速度是不变的，我有办法回答这个问题：我将在X分钟内到达哪里？
注意
我知道距离旅行=时间*速度但通过这种方式，我知道我旅行了多少公里。我想知道的是一段时间后的经纬度。
工作示例，使用 epoly.js迈克威廉姆斯的第三方库已移植到v3中
var directionDisplay;
var directionsService = new google.maps.DirectionsService（）;
var map;
var polyline = null;
$ b $函数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;
// gmarkers.push（marker）;
google.maps.event.addListener（marker，'click'，function（）{
infowindow.setContent（contentString）;
infowindow.open（map，marker）;
}）;
返回标记;
函数initialize（）{
directionsDisplay = new google.maps.DirectionsRenderer（{suppressMarkers：true}）;
var chicago = new google.maps.LatLng（41.850033，-87.6500523）;
var myOptions = {
zoom：6，
mapTypeId：google.maps.MapTypeId.ROADMAP，
center：chicago
}
map = new google .maps.Map（document.getElementById（map_canvas），myOptions）;
polyline = new google.maps.Polyline（{
path：[]，
strokeColor：'＃FF0000'，
strokeWeight：3
}）;
directionsDisplay.setMap（map）;
calcRoute（）;
函数calcRoute（）{
var start = document.getElementById（start）.value;
var end = document.getElementById（end）.value;
var travelMode = google.maps.DirectionsTravelMode.DRIVING
var request = {
origin：start，
destination：end，
travelMode：travelMode
};
directionsService.route（request，function（response，status）{
if（status == google.maps.DirectionsStatus.OK）{
polyline.setPath（[]）;
）var bounds = new google.maps.LatLngBounds（）;
startLocation = new Object（）;
endLocation = new Object（）;
directionsDisplay.setDirections（response）;
var route = response.routes [0];
var summaryPanel = document.getElementById（directions_panel）;
summaryPanel.innerHTML =;
//对于每条路线，显示摘要信息
var path = response.routes [0] .overview_path;
var legs = response.routes [0] .legs;
for（i = 0; i
startLocation.latlng = legs [i] .start_location;
startLocation.address = legs [i] .start_address;
// marker = google.maps.Marker（{map：map，position：startLocation.latlng}）;
marker = createMarker（legs [i] .start_location，start，legs [i] .start_address，green）;
}
endLocation.latlng = legs [i] .end_location;
endLocation.address = legs [i] .end_address;
var steps = legs [i] .steps;
for（j = 0; j
;
bounds.extend（nextSegment [k]）;
}
}
}
polyline.setMap（map）;
computeTotalDistance（response）;
} else {
alert（directions response+ status）;
}
}）;
}
var totalDist = 0;
var totalTime = 0;
函数computeTotalDistance（结果）{
totalDist = 0;
totalTime = 0;
var myroute = result.routes [0];
for（i = 0; i< myroute.legs.length; i ++）{
totalDist + = myroute.legs [i] .distance.value;
totalTime + = myroute.legs [i] .duration.value;
}
totalDist = totalDist / 1000.
document.getElementById（total）。innerHTML =total distance is：+ totalDist +km< br> total time is：+ （totalTime / 60）.toFixed（2）+minutes;
document.getElementById（totalTime）。value =（totalTime / 60。）。toFixed（2）;
}
函数putMarkerOnRoute（time）{
var distance =（time * 60 / totalTime）* totalDist * 1000;
// alert（Time：+ time +totalTime：+ totalTime +totalDist：+ totalDist +dist：+ distance）;
if（！marker）{
marker = createMarker（polyline.GetPointAtDistance（distance），time：+ time，marker）;
} else {
marker.setPosition（polyline.GetPointAtDistance（distance））;
marker.setTitle（time：+ time）;
}
}
/ ********************************* ************************************ \
* *
* epolys .js by Mike Williams *
*由Larry Ross更新至API v3 *
* *
* Google Maps API扩展*
* *
*添加各种方法到google.maps.Polygon和google.maps.Polyline *
* *
* .GetPointAtDistance（）会返回沿路径指定距离* b $ b *的GLatLng。 *
*距离以米为单位指定*
*如果路径短于此值，则返回null *
* *
* .GetPointsAtDistance（）返回一个GLatLng数组*
*指定的路径间隔。 *
*距离以米为单位指定*
* *
*************************** ********************************************
* *
*此Javascript由Mike Williams提供*
* Blackpool Community Church Javascript Team *
* http://www.blackpoolchurch.org/ *
* http：// econym .org.uk / gmap / *
* *
*本作品以Creative Commons License *
* http://creativecommons.org/licenses/by/2.0/uk/ *
* *
*************************************** ****************************** **
* *
*版本1.1 2007年6月6日*
*版本1.2 2007年7月1日 - 修正：边界省略顶点零*
* add：轴承*
*版本1.3 2008年11月28日add：GetPointsAtDistance（）*
*版本1.4 2009年1月12日修复：GetPointsAtDistance（）*
* 3.0版本2010年8月11日更新到v3 *
* *
\ *********************************** ********************************** /
// ===首先支持（v3）中尚未存在的方法
google.maps.LatLng.prototype.distanceFrom = function（newLatLng）{
var EarthRadiusMeters = 6378137.0; //米
var lat1 = this.lat（）;
var lon1 = this.lng（）;
var lat2 = newLatLng.lat（）;
var lon2 = newLatLng.lng（）;
var dLat =（lat2-lat1）* Math.PI / 180;
var dLon =（lon2-lon1）* Math.PI / 180;
var a = Math.sin（dLat / 2）* Math.sin（dLat / 2）+
Math.cos（lat1 * Math.PI / 180）* Math.cos（lat2 * Math。 PI / 180）*
Math.sin（dLon / 2）* Math.sin（dLon / 2）;
var c = 2 * Math.atan2（Math.sqrt（a），Math.sqrt（1-a））;
var d = EarthRadiusMeters * c;
return d;
}
google.maps.LatLng.prototype.latRadians = function（）{
return this.lat（）* Math.PI / 180;
google.maps.LatLng.prototype.lngRadians = function（）{
return this.lng（）* Math.PI / 180;
}
// ===一种以米为单位返回路径长度的方法===
google.maps.Polygon.prototype.Distance = function（）{
var dist = 0;
for（var i = 1; i< this.getPath（）。getLength（）; i ++）{
dist + = this.getPath（）。getAt（i）.distanceFrom（this.getPath （）.getAt第（i-1））;
}
return dist;
}
// ===一种方法，沿路径返回给定距离的点的GLatLng ===
// ===如果路径比指定距离短===
google.maps.Polygon.prototype.GetPointAtDistance =函数（米）{
//一些特殊情况
if（meters == 0）return this.getPath（）getAt（0）。
if（meters <0）返回null;
if（this.getPath（）。getLength（）< 2）return null;
var dist = 0;
var olddist = 0; $ i
for（var i = 1;（i
dist + = this.getPath（）。getAt（i）.distanceFrom（this.getPath（）。getAt（i-1））;
}
if（dist
}
var p1 = this.getPath（）。getAt（i-2）;
var p2 = this.getPath（）。getAt（i-1）;
var m =（meters-olddist）/（dist-olddist）;
return new google.maps.LatLng（p1.lat（）+（p2.lat（） - p1.lat（））* m，p1.lng（）+（p2.lng（） - p1.lng （））*米）;
}
// ===一种方法，它返回沿路径给定间隔的点的GLatLngs数组===
google.maps.Polygon.prototype.GetPointsAtDistance =函数（米）{
var next =米;
var points = [];
//一些特殊情况
if（meters <= 0）返回点;
var dist = 0;
var olddist = 0; $ i
（var i = 1;（i< this.getPath（）。getLength（））; i ++）{
olddist = dist;
dist + = this.getPath（）。getAt（i）.distanceFrom（this.getPath（）。getAt（i-1））;
while（dist> next）{
var p1 = this.getPath（）。getAt（i-1）;
var p2 = this.getPath（）。getAt（i）;
var m =（next-olddist）/（dist-olddist）;
points.push（new google.maps.LatLng（p1.lat（）+（p2.lat（） - p1.lat（））* m，p1.lng（）+（p2.lng（） - p1.lng（））* M））;
next + =米;
}
}
回报点;
}
// ===将上述所有函数复制到GPolyline ===
google.maps.Polyline.prototype.Distance = google.maps.Polygon.prototype。距离;
google.maps.Polyline.prototype.GetPointAtDistance = google.maps.Polygon.prototype.GetPointAtDistance;
google.maps.Polyline.prototype.GetPointsAtDistance = google.maps.Polygon.prototype.GetPointsAtDistance;
With Google API directions I can get all the information to go from one place to another and I can get all the steps as well.
But I don't know if there is a way to retrieve/calculate the position(Lat/Lng) after a given time. Assuming, to simplify, my speed is constant is there I way to answer the question: where will I be in X minutes ?
NOTE
I know that Distance travelled = Time * Speed but in this way I know how many KM I travelled. What I want to know is the (Lat/Lng) after a period of time.
解决方案
working example using GetPointAtDistance from the epoly.js third party library from Mike Williams ported to v3
var directionDisplay;
var directionsService = new google.maps.DirectionsService();
var map;
var polyline = null;
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;
// gmarkers.push(marker);
google.maps.event.addListener(marker, 'click', function() {
infowindow.setContent(contentString);
infowindow.open(map,marker);
});
return marker;
}
function initialize() {
directionsDisplay = new google.maps.DirectionsRenderer({suppressMarkers:true});
var chicago = new google.maps.LatLng(41.850033, -87.6500523);
var myOptions = {
zoom: 6,
mapTypeId: google.maps.MapTypeId.ROADMAP,
center: chicago
}
map = new google.maps.Map(document.getElementById("map_canvas"), myOptions);
polyline = new google.maps.Polyline({
path: [],
strokeColor: '#FF0000',
strokeWeight: 3
});
directionsDisplay.setMap(map);
calcRoute();
}
function calcRoute() {
var start = document.getElementById("start").value;
var end = document.getElementById("end").value;
var travelMode = google.maps.DirectionsTravelMode.DRIVING
var request = {
origin: start,
destination: end,
travelMode: travelMode
};
directionsService.route(request, function(response, status) {
if (status == google.maps.DirectionsStatus.OK) {
polyline.setPath([]);
var bounds = new google.maps.LatLngBounds();
startLocation = new Object();
endLocation = new Object();
directionsDisplay.setDirections(response);
var route = response.routes[0];
var summaryPanel = document.getElementById("directions_panel");
summaryPanel.innerHTML = "";
// For each route, display summary information.
var path = response.routes[0].overview_path;
var legs = response.routes[0].legs;
for (i=0;i<legs.length;i++) {
if (i == 0) {
startLocation.latlng = legs[i].start_location;
startLocation.address = legs[i].start_address;
// marker = google.maps.Marker({map:map,position: startLocation.latlng});
marker = createMarker(legs[i].start_location,"start",legs[i].start_address,"green");
}
endLocation.latlng = legs[i].end_location;
endLocation.address = legs[i].end_address;
var steps = legs[i].steps;
for (j=0;j<steps.length;j++) {
var nextSegment = steps[j].path;
for (k=0;k<nextSegment.length;k++) {
polyline.getPath().push(nextSegment[k]);
bounds.extend(nextSegment[k]);
}
}
}
polyline.setMap(map);
computeTotalDistance(response);
} else {
alert("directions response "+status);
}
});
}
var totalDist = 0;
var totalTime = 0;
function computeTotalDistance(result) {
totalDist = 0;
totalTime = 0;
var myroute = result.routes[0];
for (i = 0; i < myroute.legs.length; i++) {
totalDist += myroute.legs[i].distance.value;
totalTime += myroute.legs[i].duration.value;
}
totalDist = totalDist / 1000.
document.getElementById("total").innerHTML = "total distance is: "+ totalDist + " km<br>total time is: " + (totalTime / 60).toFixed(2) + " minutes";
document.getElementById("totalTime").value = (totalTime/60.).toFixed(2);
}
function putMarkerOnRoute(time) {
var distance = (time*60/totalTime) * totalDist*1000;
// alert("Time:"+time+" totalTime:"+totalTime+" totalDist:"+totalDist+" dist:"+distance);
if (!marker) {
marker = createMarker(polyline.GetPointAtDistance(distance),"time: "+time,"marker");
} else {
marker.setPosition(polyline.GetPointAtDistance(distance));
marker.setTitle("time:"+time);
}
}
v3_epoly.js
/*********************************************************************\
* *
* epolys.js by Mike Williams *
* updated to API v3 by Larry Ross *
* *
* A Google Maps API Extension *
* *
* Adds various Methods to google.maps.Polygon and google.maps.Polyline *
* *
* .GetPointAtDistance() returns a GLatLng at the specified distance *
* along the path. *
* The distance is specified in metres *
* Reurns null if the path is shorter than that *
* *
* .GetPointsAtDistance() returns an array of GLatLngs at the *
* specified interval along the path. *
* The distance is specified in metres *
* *
***********************************************************************
* *
* This Javascript is provided by Mike Williams *
* Blackpool Community Church Javascript Team *
* http://www.blackpoolchurch.org/ *
* http://econym.org.uk/gmap/ *
* *
* This work is licenced under a Creative Commons Licence *
* http://creativecommons.org/licenses/by/2.0/uk/ *
* *
***********************************************************************
* *
* Version 1.1 6-Jun-2007 *
* Version 1.2 1-Jul-2007 - fix: Bounds was omitting vertex zero *
* add: Bearing *
* Version 1.3 28-Nov-2008 add: GetPointsAtDistance() *
* Version 1.4 12-Jan-2009 fix: GetPointsAtDistance() *
* Version 3.0 11-Aug-2010 update to v3 *
* *
\*********************************************************************/
// === first support methods that don't (yet) exist in v3
google.maps.LatLng.prototype.distanceFrom = function(newLatLng) {
var EarthRadiusMeters = 6378137.0; // meters
var lat1 = this.lat();
var lon1 = this.lng();
var lat2 = newLatLng.lat();
var lon2 = newLatLng.lng();
var dLat = (lat2-lat1) * Math.PI / 180;
var dLon = (lon2-lon1) * Math.PI / 180;
var a = Math.sin(dLat/2) * Math.sin(dLat/2) +
Math.cos(lat1 * Math.PI / 180 ) * Math.cos(lat2 * Math.PI / 180 ) *
Math.sin(dLon/2) * Math.sin(dLon/2);
var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));
var d = EarthRadiusMeters * c;
return d;
}
google.maps.LatLng.prototype.latRadians = function() {
return this.lat() * Math.PI/180;
}
google.maps.LatLng.prototype.lngRadians = function() {
return this.lng() * Math.PI/180;
}
// === A method which returns the length of a path in metres ===
google.maps.Polygon.prototype.Distance = function() {
var dist = 0;
for (var i=1; i < this.getPath().getLength(); i++) {
dist += this.getPath().getAt(i).distanceFrom(this.getPath().getAt(i-1));
}
return dist;
}
// === A method which returns a GLatLng of a point a given distance along the path ===
// === Returns null if the path is shorter than the specified distance ===
google.maps.Polygon.prototype.GetPointAtDistance = function(metres) {
// some awkward special cases
if (metres == 0) return this.getPath().getAt(0);
if (metres < 0) return null;
if (this.getPath().getLength() < 2) return null;
var dist=0;
var olddist=0;
for (var i=1; (i < this.getPath().getLength() && dist < metres); i++) {
olddist = dist;
dist += this.getPath().getAt(i).distanceFrom(this.getPath().getAt(i-1));
}
if (dist < metres) {
return null;
}
var p1= this.getPath().getAt(i-2);
var p2= this.getPath().getAt(i-1);
var m = (metres-olddist)/(dist-olddist);
return new google.maps.LatLng( p1.lat() + (p2.lat()-p1.lat())*m, p1.lng() + (p2.lng()-p1.lng())*m);
}
// === A method which returns an array of GLatLngs of points a given interval along the path ===
google.maps.Polygon.prototype.GetPointsAtDistance = function(metres) {
var next = metres;
var points = [];
// some awkward special cases
if (metres <= 0) return points;
var dist=0;
var olddist=0;
for (var i=1; (i < this.getPath().getLength()); i++) {
olddist = dist;
dist += this.getPath().getAt(i).distanceFrom(this.getPath().getAt(i-1));
while (dist > next) {
var p1= this.getPath().getAt(i-1);
var p2= this.getPath().getAt(i);
var m = (next-olddist)/(dist-olddist);
points.push(new google.maps.LatLng( p1.lat() + (p2.lat()-p1.lat())*m, p1.lng() + (p2.lng()-p1.lng())*m));
next += metres;
}
}
return points;
}
// === Copy all the above functions to GPolyline ===
google.maps.Polyline.prototype.Distance = google.maps.Polygon.prototype.Distance;
google.maps.Polyline.prototype.GetPointAtDistance = google.maps.Polygon.prototype.GetPointAtDistance;
google.maps.Polyline.prototype.GetPointsAtDistance = google.maps.Polygon.prototype.GetPointsAtDistance;
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