如何使对象回到java map中的起点
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【中文标题】如何使对象回到java map中的起点【英文标题】：How to make a object back to the start point in java map 【发布时间】：2021-04-21 02:45:54 【问题描述】：我想做一些类似公共汽车跟踪的东西，它围绕一个多边形，每秒移动 2 米回到起点。并且每秒对象（？）点坐标。
我什至不知道如何开始。请帮帮我。
多边形代码：
function initMap()
map = new google.maps.Map(document.getElementById("map"),
zoom: 12,
center: lat: 0.5164426, lng: 101,4574499 ,
mapTypeId: "terrain",
);
const triangleCoords = [
lat: 0.5022181713704478, lng: 101.41882830662435 ,
lat: 0.4975231087415325, lng: 101.39433139688956 ,
lat: 0.5103834896305101, lng: 101.39412725597509 ,
lat: 0.5169157367830446, lng: 101.39923077883651 ,
lat: 0.5350835135799168, lng: 101.4035177380401 ,
lat: 0.5348793815517918, lng: 101.41984901119662 ,
];
const bermudaTriangle = new google.maps.Polygon(
paths: triangleCoords,
strokeColor: "#0000FF",
strokeOpacity: 1,
strokeWeight: 2,
fillColor: "#FF6633",
fillOpacity: 0.35,
);
bermudaTriangle.setMap(map);
bermudaTriangle.addListener("click", showArrays);
infoWindow = new google.maps.InfoWindow();
基本上如何使巴士从 lat: 0.5022181713704478, lng: 101.41882830662435 回到 lat: 0.5022181713704478, lng: 101.41882830662435 戏剧性
我所期望的：http://www.geocodezip.com/v3_animate_marker_directions.html 但它有 6 点陈述并且不断地移动
【问题讨论】：
【参考方案1】：您发布的代码有几个问题：
-
在
lng 之后map 上没有: center：`
center: lat: 0.5164426, lng 101,4574499 ,
应该是：
center: lat: 0.5164426, lng: 101,4574499 ,
PolygonOptions 中的fillColor: "#FF6633" 后面没有逗号
在PolygonOptions panths 应该是paths
要与my example保持一致，需要Polyline（而不是Polygon），这意味着您需要添加最后一个点来完成路径：
const triangleCoords = [
lat: 0.5022181713704478,
lng: 101.41882830662435
,
lat: 0.4975231087415325,
lng: 101.39433139688956
,
lat: 0.5103834896305101,
lng: 101.39412725597509
,
lat: 0.5169157367830446,
lng: 101.39923077883651
,
lat: 0.5350835135799168,
lng: 101.4035177380401
,
lat: 0.5348793815517918,
lng: 101.41984901119662
,
// duplicate of first point
lat: 0.5022181713704478,
lng: 101.41882830662435
,
];
proof of concept fiddle
为防止地图中心发生变化，请删除更改中心的代码（map.setCenter 的一个实例，map.panTo 的两个实例）：fiddle where map center not modified
要保持标记在循环周围循环，请更改“结束”条件以重新启动动画，方法是调用animate(0)：
function animate(d)
if (d > eol)
map.panTo(polyline.getPath().getAt(polyline.getPath().getLength() - 1));
marker.setPosition(polyline.getPath().getAt(polyline.getPath().getLength() - 1));
// continuous loop
animate(0);
return;
live example
代码 sn-p：
var polyline, marker;
function initMap()
addEpolyFunc();
map = new google.maps.Map(document.getElementById("map"),
zoom: 12,
center:
lat: 0.5164426,
lng: 101.4574499
,
mapTypeId: "terrain",
);
const triangleCoords = [
lat: 0.5022181713704478,
lng: 101.41882830662435
,
lat: 0.4975231087415325,
lng: 101.39433139688956
,
lat: 0.5103834896305101,
lng: 101.39412725597509
,
lat: 0.5169157367830446,
lng: 101.39923077883651
,
lat: 0.5350835135799168,
lng: 101.4035177380401
,
lat: 0.5348793815517918,
lng: 101.41984901119662
,
lat: 0.5022181713704478,
lng: 101.41882830662435
,
];
const bermudaTriangle = new google.maps.Polygon(
paths: triangleCoords,
strokeColor: "#0000FF",
strokeOpacity: 1,
strokeWeight: 2,
fillColor: "#FF6633",
fillOpacity: 0.35,
);
bermudaTriangle.setMap(map);
infoWindow = new google.maps.InfoWindow();
polyline = new google.maps.Polyline(
// map: map,
path: triangleCoords,
strokeColor: "#0000FF",
strokeOpacity: 1,
strokeWeight: 2,
);
marker = new google.maps.Marker(
position: polyline.getPath().getAt(0),
map: map
)
startAnimation();
var step = 50; // 5; // metres
var tick = 100; // milliseconds
var eol;
var k = 0;
var stepnum = 0;
var speed = "";
var lastVertex = 1;
//=============== animation functions ======================
function updatePoly(d)
// Spawn a new polyline every 20 vertices, because updating a 100-vertex poly is too slow
if (poly2.getPath().getLength() > 20)
poly2 = new google.maps.Polyline([polyline.getPath().getAt(lastVertex - 1)]);
if (polyline.GetIndexAtDistance(d) < lastVertex + 2)
if (poly2.getPath().getLength() > 1)
poly2.getPath().removeAt(poly2.getPath().getLength() - 1)
poly2.getPath().insertAt(poly2.getPath().getLength(), polyline.GetPointAtDistance(d));
else
poly2.getPath().insertAt(poly2.getPath().getLength(), polyline.getPath().getAt(polyline.getPath().getLength() - 1));
function animate(d)
if (d > eol)
map.panTo(polyline.getPath().getAt(polyline.getPath().getLength() - 1));
marker.setPosition(polyline.getPath().getAt(polyline.getPath().getLength() - 1));
// continuous loop
animate(0);
return;
var p = polyline.GetPointAtDistance(d);
map.panTo(p);
marker.setPosition(p);
updatePoly(d);
timerHandle = setTimeout("animate(" + (d + step) + ")", tick);
function startAnimation()
eol = google.maps.geometry.spherical.computeLength(polyline.getPath());
map.setCenter(polyline.getPath().getAt(0));
poly2 = new google.maps.Polyline(
path: [polyline.getPath().getAt(0)],
strokeColor: "#0000FF",
strokeWeight: 10
);
setTimeout("animate(50)", 2000); // Allow time for the initial map display
function addEpolyFunc()
//=============== ~animation funcitons =====================
// from epoly_v3.js
// modified to use geometry library for length of line segments
// === A method which returns the Vertex number at a given distance along the path ===
// === Returns null if the path is shorter than the specified distance ===
google.maps.Polyline.prototype.GetIndexAtDistance = function(metres)
// some awkward special cases
if (metres == 0) return this.getPath().getAt(0);
if (metres < 0) return null;
var dist = 0;
var olddist = 0;
for (var i = 1;
(i < this.getPath().getLength() && dist < metres); i++)
olddist = dist;
dist += google.maps.geometry.spherical.computeDistanceBetween(this.getPath().getAt(i), this.getPath().getAt(i - 1));
if (dist < metres)
return null;
return i;
// === 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.Polyline.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 += google.maps.geometry.spherical.computeDistanceBetween(this.getPath().getAt(i), 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 the length of a path in metres ===
google.maps.Polyline.prototype.Distance = function()
var dist = 0;
for (var i = 1; i < this.getPath().getLength(); i++)
dist += google.maps.geometry.spherical.computeDistanceBetween(this.getPath().getAt(i), this.getPath().getAt(i - 1));
return dist;
/* Always set the map height explicitly to define the size of the div
* element that contains the map. */
#map
height: 100%;
/* Optional: Makes the sample page fill the window. */
html,
body
height: 100%;
margin: 0;
padding: 0;
<!DOCTYPE html>
<html>
<head>
<title>Simple Polygon</title>
<script src="https://polyfill.io/v3/polyfill.min.js?features=default"></script>
<script src="https://maps.googleapis.com/maps/api/js?key=AIzaSyCkUOdZ5y7hMm0yrcCQoCvLwzdM6M8s5qk&callback=initMap&libraries=geometry&v=weekly" defer></script>
<!-- jsFiddle will insert css and js -->
</head>
<body>
<div id="map"></div>
</body>
</html>【讨论】：
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