How to create polylines between all markers from database with start Latlng and End Latlng?

Question

I have to make map with gadgets that gets voltage each of them from previous point. I have records in my database with lat and lng. I store gadgets with markers on the map with custom icons and windowInfo, but i want to get previous point`s lat and lng and make polyline between previous point and the new one. How can i do this ?

This is my code of index

var customIcons = {
  контрагент: {
    icon: 'img/contragent.png'
  },
  switch_16p: {
    icon: 'img/switch_16p.png'
  },
  switch_8p: {
    icon: 'img/switch_8p.png'
  },
  switch_6p:{
    icon: 'img/switch_6p.png'
  }
};

function load(select) {


  var map = new google.maps.Map(document.getElementById("map"), {
    center: new google.maps.LatLng(43.8496, 25.9552),
    zoom: 14,
    mapTypeId: 'roadmap'
  });
  var infoWindow = new google.maps.InfoWindow;



  // Change this depending on the name of your PHP file
  downloadUrl("settings_map.php", function(data) {
    var xml = data.responseXML;
    var markers = xml.documentElement.getElementsByTagName("marker");
    for (var i = 0; i < markers.length; i++) {
      var opis_id = markers[i].getAttribute("opis_id");
      var address = markers[i].getAttribute("address");
      var type = markers[i].getAttribute("type");
      var kvartal = markers[i].getAttribute("kvartal");
      var gadget = markers[i].getAttribute("gadget");
      var point = new google.maps.LatLng(
          parseFloat(markers[i].getAttribute("lat")),
          parseFloat(markers[i].getAttribute("lng")));
      var html = "<b>Опис ID</b> - " + opis_id + "<br/> <br/><b>Адрес:</b> " + address + "<br/><b>Квартал:</b> " + kvartal + "<br><b>У-во: </b>" + gadget;


      var icon = customIcons[type] || {};
      var marker = new google.maps.Marker({
        map: map,
        position: point,
        icon: icon.icon
      });

      bindInfoWindow(marker, map, infoWindow, html);

    }
  });
}



function bindInfoWindow(marker, map, infoWindow, html) {
  google.maps.event.addListener(marker, 'click', function() {

    infoWindow.setContent(html);
    infoWindow.open(map, marker);

  });
}

function downloadUrl(url, callback) {
  var request = window.ActiveXObject ?
      new ActiveXObject('Microsoft.XMLHTTP') :
      new XMLHttpRequest;

  request.onreadystatechange = function() {
    if (request.readyState == 4) {
      request.onreadystatechange = doNothing;
      callback(request, request.status);
    }
  };

  request.open('GET', url, true);
  request.send(null);
}

function doNothing() {

}


        var map = new google.maps.Map(document.getElementById('map'), {
          zoom: 3,
          center: {lat: 0, lng: -180},
          mapTypeId: 'terrain'
        });

Answer 1

1. define an array to track the markers already added to the map:

var gmarkers = [];

2. add the markers to that array, after the first create a polyline:

gmarkers.push(marker);
if (i > 0) {
  var polyline = new google.maps.Polyline({
    path: [gmarkers[i - 1].getPosition(), marker.getPosition()],
    map: map
  });
}

proof of concept fiddle

code snippet:

 var map; var gmarkers = []; function load() { map = new google.maps.Map(document.getElementById("map"), { center: new google.maps.LatLng(43.8496, 25.9552), zoom: 14, mapTypeId: 'roadmap' }); var infoWindow = new google.maps.InfoWindow; var xml = parseXml(xmlStr); var markers = xml.documentElement.getElementsByTagName("marker"); var bounds = new google.maps.LatLngBounds(); for (var i = 0; i < markers.length; i++) { var opis_id = "opis_id"; var address = markers[i].getAttribute("address"); var type = markers[i].getAttribute("type"); var kvartal = "kvartal"; var gadget = "gadget"; var point = new google.maps.LatLng( parseFloat(markers[i].getAttribute("lat")), parseFloat(markers[i].getAttribute("lng"))); bounds.extend(point); var html = "<b>Опис ID</b> - " + opis_id + "<br/> <br/><b>Адрес:</b> " + address + "<br/><b>Квартал:</b> " + kvartal + "<br><b>У-во: </b>" + gadget; var marker = new google.maps.Marker({ map: map, position: point, }); bindInfoWindow(marker, map, infoWindow, html); gmarkers.push(marker); if (i > 0) { var polyline = new google.maps.Polyline({ path: [gmarkers[i - 1].getPosition(), marker.getPosition()], map: map }); } } map.fitBounds(bounds); } function bindInfoWindow(marker, map, infoWindow, html) { google.maps.event.addListener(marker, 'click', function() { infoWindow.setContent(html); infoWindow.open(map, marker); }); } function parseXml(str) { if (window.ActiveXObject) { var doc = new ActiveXObject('Microsoft.XMLDOM'); doc.loadXML(str); return doc; } else if (window.DOMParser) { return (new DOMParser).parseFromString(str, 'text/xml'); } } google.maps.event.addDomListener(window, 'load', load); var xmlStr = '<?xml version="1.0"?><markers><marker name="Round Table Pizza: Mountain View" address="570 N Shoreline Blvd, Mountain View, CA" lat="37.402653" lng="-122.079353" distance="0.38091455044131"/><marker name="Kapp\\'s Pizza Bar &amp; Grill" address="191 Castro St, Mountain View, CA" lat="37.393887" lng="-122.078918" distance="0.5596115438175"/><marker name="Amici\\'s East Coast Pizzeria" address="790 Castro St, Mountain View, CA" lat="37.387138" lng="-122.083237" distance="1.0796074495809"/><marker name="Frankie Johnnie &amp; Luigo Too" address="939 W El Camino Real, Mountain View, CA" lat="37.386337" lng="-122.085823" distance="1.2044231336188"/><marker name="Tony &amp; Alba\\'s Pizza &amp; Pasta" address="619 Escuela Ave, Mountain View, CA" lat="37.394012" lng="-122.095528" distance="1.3156538737837"/><marker name="Round Table Pizza: Sunnyvale-Mary-Central Expy" address="415 N Mary Ave, Sunnyvale, CA" lat="37.390038" lng="-122.042030" distance="1.84565061776"/><marker name="Oregano\\'s Wood-Fired Pizza" address="4546 El Camino Real, Los Altos, CA" lat="37.401726" lng="-122.114647" distance="2.2887425990519"/><marker name="Pizz\\'a Chicago" address="4115 El Camino Real, Palo Alto, CA" lat="37.414104" lng="-122.126221" distance="3.0702714925465"/><marker name="California Pizza Kitchen" address="531 Cowper St, Palo Alto, CA" lat="37.448074" lng="-122.158813" distance="5.744901789628"/><marker name="Patxi\\'s Chicago Pizza" address="441 Emerson St, Palo Alto, CA" lat="37.445148" lng="-122.163551" distance="5.8508447055485"/><marker name="Applewood Pizza 2 Go" address="1001 El Camino Real, Menlo Park, CA" lat="37.452965" lng="-122.181725" distance="6.9830185240251"/><marker name="Fiorillo\\'s Restaurant" address="638 El Camino Real, Santa Clara, CA" lat="37.354603" lng="-121.942574" distance="7.8305245099868"/><marker name="Round Table Pizza" address="4302 Moorpark Ave, San Jose, CA" lat="37.315903" lng="-121.977928" distance="7.8357853019702"/><marker name="Tony &amp; Alba\\'s Pizza &amp; Pasta" address="3137 Stevens Creek Blvd, San Jose, CA" lat="37.323296" lng="-121.951645" distance="8.534766437601"/><marker name="Pizza Antica" address="334 Santana Row # 1065, San Jose, CA" lat="37.321793" lng="-121.947739" distance="8.7673701809137"/><marker name="Amici\\'s East Coast Pizzeria" address="225 W Santa Clara St, San Jose, CA" lat="37.334702" lng="-121.894043" distance="10.826482447706"/><marker name="Pizz\\'a Chicago" address="155 W San Fernando St, San Jose, CA" lat="37.333279" lng="-121.891678" distance="10.985777935382"/><marker name="House of Pizza" address="527 S Almaden Ave, San Jose, CA" lat="37.326351" lng="-121.888168" distance="11.368626024055"/><marker name="Amici\\'s East Coast Pizzeria" address="226 Redwood Shores Pkwy, Redwood City, CA" lat="37.520515" lng="-122.252258" distance="12.8643535655"/></markers>'; 

 html, body, #map { height: 100%; width: 100%; margin: 0px; padding: 0px } 

 <script src="https://maps.googleapis.com/maps/api/js"></script> <div id="map"></div>