Loading javascript content dynamically into Google map javascript

**stereotyyppi** · 01-15-2008, 08:05 AM

Hi, I'm using ajax with php for getting information from mysql database. My problem is how to put the code (latitudes, longitudes) into google javascript file (not into div in the body section) and also how to load the map to see changes.

The purpose of this script is to show ships route on google map on defined date (javascript).

So it should put "new GLatLng(lat,long)," - values into javascript file.

------------------- index.html: -------------------------

HTML Code:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
  <head>
    <meta http-equiv="content-type" content="text/html; charset=utf-8"/>
    <title>Google Maps JavaScript API Example</title>
    <script src="selectuser.js"></script>
    <script src="http://maps.google.com/maps?file=api&amp;v=2&amp;key=ABQIAAAA8932eZOB5JEYtvZPasq4FxQ54HRG6gq8VpzycMbCIkcuTGCE9hRMM
9j97YB3eghRasY7q3LcbbWseg"
      type="text/javascript"></script>
      <script type="text/javascript">
	function load() {
        //<![CDATA[
	if (GBrowserIsCompatible()) {
		var map = new GMap2(document.getElementById("map"));
		map.addControl(new GSmallMapControl());
		map.addControl(new GMapTypeControl());
		map.setCenter(new   
 GLatLng(60.1766666666667,25.776666666666), 6);
		var polyline = new GPolyline([                           
********************** Here is where the code should be put **********************
	new GLatLng(60.1592,24.9227),
	new GLatLng(60.1592,12.4257),
	], "#ff0000", 3, 0.9);
	map.addOverlay(polyline);
      }
      //]]>
    }


    </script>
    
  </head>
  <body onload="load()" onunload="GUnload()">
    <h2>Arandan matka Combine4/2007</h2>
    Alkoi: 2007-12-10 12:30:00 ja p&auml;&auml;ttyi: 2007-12-14 07:35:00
    <h3>Hae tiedot:</h3>
    Anna aloitusaika, askelv&auml;li (yksi askel on noin 10s) ja esitett&auml;vien rivien m&auml;&auml;r&auml;. 
  <form>
 
	steppi: <input id="steppi" name="steppi" value="60" type="text"> Alkuaika: <input id="startti" name="startti" type="text" value="2007-12-10 12:30:00"> limit: <input id="limitti" name="limitti" value="10" type="text">
   
	<input type="button" value="Hae" onclick="showUser(steppi.value, startti.value, limitti.value)" ></form>
	<div id="txtHint"></div>	
	<div id="map" style="width: 500px; height: 400px"></div>
  </body>
</html>

---------------------- selectuser.js: ----------------------------

Code:

var xmlHttp

function showUser(steppi, start, limitti)
{ 
xmlHttp=GetXmlHttpObject()
if (xmlHttp==null)
 {
 alert ("Browser does not support HTTP Request")
 return
 }
var url="getuser.php"
url= url + "?q=" + steppi + "&s=" + start + "&l=" + limitti
url=url+"&sid="+Math.random()
xmlHttp.onreadystatechange=stateChanged 
xmlHttp.open("GET",url,true)
xmlHttp.send(null)
}

function stateChanged() 
{ 
if (xmlHttp.readyState==4 || xmlHttp.readyState=="complete")
 { 
 document.getElementById("txtHint").innerHTML=xmlHttp.responseText 
 } 
}

function GetXmlHttpObject()
{
var xmlHttp=null;
try
 {
 // Firefox, Opera 8.0+, Safari
 xmlHttp=new XMLHttpRequest();
 }
catch (e)
 {
 //Internet Explorer
 try
  {
  xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
  }
 catch (e)
  {
  xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
  }
 }
return xmlHttp;
}

--------------------------- getuser.php ----------------------------------

PHP Code:


<?php

$q=$_GET["q"];

$s=$_GET["s"];

$l=$_GET["l"];

$con = mysql_connect('localhost', 'user', 'password');

if (!$con)

 {

 die('Could not connect: ' . mysql_error());

 }



mysql_select_db("awc", $con);



$sql="SELECT * FROM locations WHERE mod(Id,".$q." ) = 0 AND str_to_date('".$s."','%Y-%m-%d %T') > ReceiveTime limit " .$l. "";



// str_to_date('".$s."','%Y-%m-%d %k:%i:%s')

$result = mysql_query($sql);



echo "<table border='1'>

<tr>

<th>Id</th>

<th>Latitude</th>

<th>Longitude</th>

<th>Datumcode</th>

<th>ReceiveTime</th>

</tr>";



while($row = mysql_fetch_array($result))

 {

 echo "<tr>";

 echo "<td>" . $row['Id'] . "</td>";

 echo "<td>" . $row['Latitude'] . "</td>";

 echo "<td>" . $row['Longitude'] . "</td>";

 echo "<td>" . $row['DatumCode'] . "</td>";

 echo "<td>" . $row['ReceiveTime'] . "</td>";

 echo "</tr>";

 }

echo "</table>";



mysql_close($con);

?>

**pman** · 01-16-2008, 01:11 AM

I assume that you are able to get the latitude and longitude information from your database using ajax. Once you have the data it will invoke your stateChanged() function

In there you can call another function that can add the polylines directly on the google map, or you can do it in that function as well. Just make sure that you are able to access the "map" variable, which created the map. Create the polylines just like you did in your "load()" function

var polyline = new GPolyline([.....

now add the polylines to your map.

You may have to remove the polylines using map.removeOverlay method and then add it.

Let me know if this helps.

**stereotyyppi** · 01-16-2008, 12:40 PM

Hi, thanks for reply.

I did as you said, but the map is drawn empty. Maybe The google script doesn't support string code that "var coordinates" has.

------------- Here is the php code: ------------- (getuser.php)

PHP Code:


<?php

$q=$_GET["q"];

$s=$_GET["s"];

$l=$_GET["l"];

$con = mysql_connect('localhost', 'username', 'password');

if (!$con)

 {

 die('Could not connect: ' . mysql_error());

 }



mysql_select_db("awc", $con);



$sql="SELECT * FROM locations WHERE mod(Id,".$q." ) = 0 AND str_to_date('".$s."','%Y-%m-%d %T') > ReceiveTime limit " .$l. "";



// str_to_date('".$s."','%Y-%m-%d %k:%i:%s')

$result = mysql_query($sql);







while($row = mysql_fetch_array($result))

 {



 echo "new Glatlng(" . $row['Latitude'] . "," . $row['Longitude'] . "),";



 }





mysql_close($con);

?>

--------------- And-here is the javascript: -------------- (selectuser.js)

Code:

var xmlHttp

function showUser(steppi, start, limitti)
{ 
xmlHttp=GetXmlHttpObject()
if (xmlHttp==null)
 {
 alert ("Browser does not support HTTP Request")
 return
 }
var url="getuser.php"
url= url + "?q=" + steppi + "&s=" + start + "&l=" + limitti
url=url+"&sid="+Math.random()
xmlHttp.onreadystatechange=stateChanged 
xmlHttp.open("GET",url,true)
xmlHttp.send(null)
}

function stateChanged() 
{ 
if (xmlHttp.readyState==4 || xmlHttp.readyState=="complete")
 {  
  
  var coordinates = xmlHttp.responseText;
  	
        if (GBrowserIsCompatible()) {
		var map = new GMap2(document.getElementById("map"));
		map.addControl(new GSmallMapControl());
		map.addControl(new GMapTypeControl());
		map.setCenter(new GLatLng(60.1766666666667,25.776666666666), 6);
		var polyline = new GPolyline([                           
			
	new GLatLng(60.1592,24.9227),
	+ coordinates +
	new GLatLng(60.1592,12.9257),
	], "#ff0000", 3, 0.9);
	map.addOverlay(polyline);
      }
}
}


function GetXmlHttpObject()
{
var xmlHttp=null;
try
 {
 // Firefox, Opera 8.0+, Safari
 xmlHttp=new XMLHttpRequest();
 }
catch (e)
 {
 //Internet Explorer
 try
  {
  xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
  }
 catch (e)
  {
  xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
  }
 }
return xmlHttp;
}

---------------- And lastly index.html --------------------

HTML Code:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
  <head>
    <meta http-equiv="content-type" content="text/html; charset=utf-8"/>
    <title>Google Maps JavaScript API Example</title>
    <script src="selectuser.js"></script>
    <script src="http://maps.google.com/maps?file=api&amp;v=2&amp;key=ABQIAAAA8932eZOB5JEYtvZPasq4FxQ54HRG6gq8VpzycMbCIkcuTGCE9hRMM
9j97YB3eghRasY7q3LcbbWseg"
      type="text/javascript"></script>

    
  </head>
  <body>
    <h2>Arandan matka Combine4/2007</h2>
    Alkoi: 2007-12-10 12:30:00 ja p&auml;&auml;ttyi: 2007-12-14 07:35:00
    <h3>Hae tiedot:</h3>
    Anna aloitusaika, askelv&auml;li (yksi askel on noin 10s) ja esitett&auml;vien rivien m&auml;&auml;r&auml;. 
	
    <form>
 
	steppi: <input id="steppi" name="steppi" value="60" type="text"> Alkuaika: <input id="startti" name="startti" type="text" value="2009-12-10 12:30:00"> limit: <input id="limitti" name="limitti" value="10" type="text">
   
	<input type="button" value="Hae" onclick="showUser(steppi.value, startti.value, limitti.value);load()" >
	


	<div id="map" style="width: 500px; height: 400px"></div>
  </body>
</html>

**pman** · 01-17-2008, 01:30 AM

Just a suggestion. Add the following in your external javascript file and call the load function like you had it before as body onLoad

HTML Code:

       var map ;
        var polyline ;

	function load() {
	if (GBrowserIsCompatible()) {
		map = new GMap2(document.getElementById("map"));
		map.addControl(new GSmallMapControl());
		map.addControl(new GMapTypeControl());
		map.setCenter(new   
 GLatLng(60.1766666666667,25.776666666666), 6);
		var polyline = new GPolyline([
	new GLatLng(60.1592,24.9227),
	new GLatLng(60.1592,12.4257),
	], "#ff0000", 3, 0.9);
	map.addOverlay(polyline);
      }
    }
}

Now, when the body loads, your google map should be showing up. Let's try modifying the following function

HTML Code:

function stateChanged() 
{ 
if (xmlHttp.readyState==4 || xmlHttp.readyState=="complete")
 { 
     var coordinates = xmlHttp.responseText;
     map.removeOverlay(polyline) ;
     polyline = new GPolyline([                           
			
	new GLatLng(60.1592,24.9227),
	+ coordinates +
	new GLatLng(60.1592,12.9257),
	], "#ff0000", 3, 0.9);

     map.addOverlay(polyline);
 }

I know it's almost the same as before. You should've been able to see the map instead of having it empty.

polyline = new GPolyline([

new GLatLng(60.1592,24.9227),
+ coordinates +
new GLatLng(60.1592,12.9257),
], "#ff0000", 3, 0.9);

I don't think the above is valid syntax. Did you try debugging your script and see if your had syntax error in these lines.

I think what you can do is, when you are getting the coordinates from your database, instead of echoing it like below:

echo "new Glatlng(" . $row['Latitude'] . "," . $row['Longitude'] . "),";

do it without the "new Glatlng" part. Simply return the actual values separated by some special characters. Then in your stateChanged function in your javascript, when you get all the values in

var coordinates = xmlHttp.responseText;

You can parse through all the values and then go ahead from there.

Do you have a link you can post?

**stereotyyppi** · 02-11-2008, 02:38 PM

Hi, I have now working version in this site:

http://gmaps.fimr.fi/cruises/awc.html

only problem is that when zoomed in the gpolyline disappears. This might be bug in google Map api.

Sincerely Juha

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