Animating Symbol on Polyline with GeoJson Using Google Map Api v.3 - google-maps-api-3

Question

i have geojson like this :
{
"type": "FeatureCollection",
"crs": { "type": "name", "properties": { "name": "urn:ogc:def:crs:OGC:1.3:CRS84" } },
"features": [
{ "type": "Feature", "properties": { "Name": "Saluran I", "descriptio": null, "timestamp": null, "begin": null, "end": null, "altitudeMo": null, "tessellate": 1, "extrude": -1, "visibility": -1, "drawOrder": null, "icon": null }, "geometry": { "type": "LineString", "coordinates": [ [ 115.16149264388849, -8.692345779607091 ], [ 115.1619799975747, -8.693099022961922 ], [ 115.1621209969948, -8.693450580043523 ], [ 115.1621893956145, -8.69367970180001 ], [ 115.1622369286341, -8.693885376054253 ], [ 115.16248624315379, -8.694125330077087 ], [ 115.1625293838875, -8.694297689361708 ], [ 115.1625662929434, -8.694480291402353 ], [ 115.1638244075253, -8.694489484612449 ] ] } },
{ "type": "Feature", "properties": { "Name": "Saluran II", "descriptio": null, "timestamp": null, "begin": null, "end": null, "altitudeMo": null, "tessellate": 1, "extrude": -1, "visibility": -1, "drawOrder": null, "icon": null }, "geometry": { "type": "LineString", "coordinates": [ [ 115.1647420393289, -8.691263798416188 ], [ 115.16480885306601, -8.691910749059817 ], [ 115.1648021389716, -8.692020041570267 ], [ 115.16476460026691, -8.692197857370241 ], [ 115.16467300953239, -8.692311184386924 ], [ 115.1645832229062, -8.692570845169653 ], [ 115.164590403574, -8.69280000074686 ], [ 115.1642184661912, -8.692878192437396 ], [ 115.16418831658579, -8.693471791565786 ], [ 115.16411080877791, -8.69417746825723 ], [ 115.1639500244154, -8.694469415766308 ], [ 115.1638498474275, -8.69450385891758 ], [ 115.1637726241196, -8.6949183073729 ], [ 115.1637482310352, -8.695106949243888 ], [ 115.16369576938609, -8.695516868583109 ], [ 115.1633930487843, -8.695552277605064 ], [ 115.1628619559151, -8.695616245099258 ], [ 115.1628453449146, -8.695861398016726 ], [ 115.1625531407406, -8.695981675836846 ], [ 115.1619167160671, -8.696110249672243 ], [ 115.1621001879372, -8.697348692504496 ], [ 115.1619454016469, -8.697429501488445 ] ] } },
{ "type": "Feature", "properties": { "Name": "Saluran III", "descriptio": null, "timestamp": null, "begin": null, "end": null, "altitudeMo": null, "tessellate": 1, "extrude": -1, "visibility": -1, "drawOrder": null, "icon": null }, "geometry": { "type": "LineString", "coordinates": [ [ 115.1649918428157, -8.698726927918452 ], [ 115.1647717936939, -8.698771893626452 ], [ 115.16464767674699, -8.698766178177538 ], [ 115.164531974608, -8.698766747854149 ], [ 115.1643076171094, -8.698759607942607 ], [ 115.1639182931609, -8.698808262913275 ], [ 115.1637251462856, -8.69887278452787 ], [ 115.1633890383243, -8.698973728970067 ], [ 115.1626822904817, -8.699201749498535 ], [ 115.1626359629325, -8.699082282748639 ], [ 115.1621957225977, -8.698410881596306 ], [ 115.16193358395429, -8.69743434218265 ] ] } }
]
}
i can showing that geojson on my map,
line.loadGeoJson(urlBase + 'peta/aliran.geojson');
// styling features aliran
line.setStyle(function(feature){
return {
strokeColor : '#0000FF',
strokeWeight : 5,
zIndex : 1
}
});
// set map;
line.setMap(map);
but i have problem when i want to animating symbols on the line like this : https://developers.google.com/maps/documentation/javascript/examples/overlay-symbol-animate. could anybody help me ?

Answer 1

Leveraging the code in this related example (which animates a marker along a polyline from the directions service) to animate a symbol along one of the polylines in your data:
proof of concept fiddle
code snippet:
var map;
var position;
var marker = null;
var polyline = null;
var poly2 = null;
var speed = 0.000005,
wait = 1;
var infowindow = null;
var myPano;
var panoClient;
var nextPanoId;
var timerHandle = null;
var polyline;
function initialize() {
map = new google.maps.Map(
document.getElementById("map_canvas"), {
center: new google.maps.LatLng(37.4419, -122.1419),
zoom: 13,
mapTypeId: google.maps.MapTypeId.ROADMAP
});
var bounds = new google.maps.LatLngBounds();
map.data.addListener('addfeature', function(e) {
processPoints(e.feature.getGeometry(), bounds.extend, bounds);
if (e.feature.getGeometry().getType() == "LineString") {
polyline = new google.maps.Polyline({
map: map,
path: e.feature.getGeometry().getArray(),
strokeWeight: 5,
strokeOpacity: 0.4,
strokeColor: 'red'
});
marker = createMarker(polyline.getPath().getAt(0), "here", "marker text");
setTimeout(startAnimation, 2000);
}
map.fitBounds(bounds);
});
// var line = google.maps.Data;
map.data.addGeoJson(geoJson);
// styling features aliran
map.data.setStyle(function(feature) {
return {
strokeColor: '#0000FF',
strokeWeight: 1,
zIndex: 1
}
});
// set map;
map.data.setMap(map);
}
var step = 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(endLocation.latlng);
marker.setPosition(endLocation.latlng);
return;
}
var p = polyline.GetPointAtDistance(d);
map.panTo(p);
marker.setPosition(p);
updatePoly(d);
timerHandle = setTimeout("animate(" + (d + step) + ")", tick);
}
function startAnimation() {
if (timerHandle) clearTimeout(timerHandle);
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(0)", tick); // Allow time for the initial map display
}
function processPoints(geometry, callback, thisArg) {
if (geometry instanceof google.maps.LatLng) {
callback.call(thisArg, geometry);
} else if (geometry instanceof google.maps.Data.Point) {
callback.call(thisArg, geometry.get());
} else {
geometry.getArray().forEach(function(g) {
processPoints(g, callback, thisArg);
});
}
}
// ==================================================
function createMarker(latlng, label, html) {
var contentString = '<b>' + label + '</b><br>' + html;
var marker = new google.maps.Marker({
position: latlng,
map: map,
title: label,
icon: {
path: google.maps.SymbolPath.CIRCLE,
scale: 8,
strokeColor: '#393'
},
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;
}
google.maps.event.addDomListener(window, "load", initialize);
var geoJson = {
"type": "FeatureCollection",
"crs": {
"type": "name",
"properties": {
"name": "urn:ogc:def:crs:OGC:1.3:CRS84"
}
},
"features": [{
"type": "Feature",
"properties": {
"Name": "Saluran II",
"descriptio": null,
"timestamp": null,
"begin": null,
"end": null,
"altitudeMo": null,
"tessellate": 1,
"extrude": -1,
"visibility": -1,
"drawOrder": null,
"icon": null
},
"geometry": {
"type": "LineString",
"coordinates": [
[115.1647420393289, -8.691263798416188],
[115.16480885306601, -8.691910749059817],
[115.1648021389716, -8.692020041570267],
[115.16476460026691, -8.692197857370241],
[115.16467300953239, -8.692311184386924],
[115.1645832229062, -8.692570845169653],
[115.164590403574, -8.69280000074686],
[115.1642184661912, -8.692878192437396],
[115.16418831658579, -8.693471791565786],
[115.16411080877791, -8.69417746825723],
[115.1639500244154, -8.694469415766308],
[115.1638498474275, -8.69450385891758],
[115.1637726241196, -8.6949183073729],
[115.1637482310352, -8.695106949243888],
[115.16369576938609, -8.695516868583109],
[115.1633930487843, -8.695552277605064],
[115.1628619559151, -8.695616245099258],
[115.1628453449146, -8.695861398016726],
[115.1625531407406, -8.695981675836846],
[115.1619167160671, -8.696110249672243],
[115.1621001879372, -8.697348692504496],
[115.1619454016469, -8.697429501488445]
]
}
}]
};
/*********************************************************************\
* *
* 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 *
* *
* .Contains(latlng) returns true is the poly contains the specified *
* GLatLng *
* *
* .Area() returns the approximate area of a poly that is *
* not self-intersecting *
* *
* .Distance() returns the length of the poly path *
* *
* .Bounds() returns a GLatLngBounds that bounds the poly *
* *
* .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 *
* *
* .GetIndexAtDistance() returns the vertex number at the specified *
* distance along the path. *
* The distance is specified in metres *
* Returns null if the path is shorter than that *
* *
* .Bearing(v1?,v2?) returns the bearing between two vertices *
* if v1 is null, returns bearing from first to last *
* if v2 is null, returns bearing from v1 to next *
* *
* *
***********************************************************************
* *
* 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 *
* *
\*********************************************************************/
// === 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 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;
}
html,
body,
#map_canvas {
height: 100%;
width: 100%;
margin: 0px;
padding: 0px
}
<script src="https://maps.googleapis.com/maps/api/js?libraries=geometry&key=AIzaSyCkUOdZ5y7hMm0yrcCQoCvLwzdM6M8s5qk"></script>
<input type="button" value="restart animation" onclick="startAnimation()" />
<div id="map_canvas"></div>