Google Maps API v3: How to Set Zoom Level And Map Center To User Submitted Location?

Question

I have used this tutorial from Google to build a web app that finds the closest store from the user entered location:

http://code.google.com/apis/maps/articles/phpsqlsearch_v3.html

I have my app almost working the way I want it, upon page load, the map is loaded, centered and set to zoom level 6 and the user fills out the form with their location.

The app then pulls all the store info from the db and populates the map with a marker for each.

The zoom level seems to decrease aswell but I can't find this in the code anywhere.

What I actually want to do on submit is zoom in to zoom level 6 and center the map to the latitude and longitude of the user entered location and output info on the nearest stores, e.g the nearest 5. I was wondering if anyone here knew how to implement this feature?

index.php

<div>
    <input type="text" id="addressInput" size="50"/>
    <input type="hidden" id="radiusSelect" value="5"/>
    <input type="button" onclick="searchLocations()" value="Search"/>
</div>
<div><select id="locationSelect" style="width:100%;visibility:hidden"></select></div>
<div id="map" style="width:100%; height:50%"></div>



<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>
<script src="http://maps.google.com/maps/api/js?sensor=false" type="text/javascript"></script>
<script type="text/javascript">
//<![CDATA[
var map;
var markers = [];
var infoWindow;
var locationSelect;

function load() {
  map = new google.maps.Map(document.getElementById("map"), {
    center: new google.maps.LatLng(54.600939134593, -2.399894114594),
    zoom: 6,
    mapTypeId: 'roadmap',
    mapTypeControlOptions: {style: google.maps.MapTypeControlStyle.DROPDOWN_MENU}
  });
  infoWindow = new google.maps.InfoWindow();

  locationSelect = document.getElementById("locationSelect");
  locationSelect.onchange = function() {
    var markerNum = locationSelect.options[locationSelect.selectedIndex].value;
    if (markerNum != "none"){
      google.maps.event.trigger(markers[markerNum], 'click');
    }
  };
}

function searchLocations() {
 var address = document.getElementById("addressInput").value;
 var geocoder = new google.maps.Geocoder();
 geocoder.geocode({address: address}, function(results, status) {
   if (status == google.maps.GeocoderStatus.OK) {
    searchLocationsNear(results[0].geometry.location);
   } else {
     alert(address + ' not found');
   }
 });
}

function clearLocations() {
 infoWindow.close();
 for (var i = 0; i < markers.length; i++) {
   markers[i].setMap(null);
 }
 markers.length = 0;

 locationSelect.innerHTML = "";
 var option = document.createElement("option");
 option.value = "none";
 option.innerHTML = "See all results:";
 locationSelect.appendChild(option);
}

function searchLocationsNear(center) {
 clearLocations(); 

 var radius = document.getElementById('radiusSelect').value;
 var searchUrl = 'phpsqlsearch_genxml.php?lat=' + center.lat() + '&lng=' + center.lng() + '&radius=' + radius;
 downloadUrl(searchUrl, function(data) {
   var xml = parseXml(data);
   var markerNodes = xml.documentElement.getElementsByTagName("marker");
   var bounds = new google.maps.LatLngBounds();
   for (var i = 0; i < markerNodes.length; i++) {
     var town = markerNodes[i].getAttribute("town");
     var postcode = markerNodes[i].getAttribute("postcode");
     var name = markerNodes[i].getAttribute("name");
     var address = markerNodes[i].getAttribute("address");
     var distance = parseFloat(markerNodes[i].getAttribute("distance"));
     var latlng = new google.maps.LatLng(
          parseFloat(markerNodes[i].getAttribute("lat")),
          parseFloat(markerNodes[i].getAttribute("lng")));

    var id = markerNodes[i].getAttribute("id");
    var fname = markerNodes[i].getAttribute("fname");
    var link = '<a href="http://www.domain.co.uk/stores/' + fname + '-' + id + '.html" target="_blank" title="Store: ' + town + '">More info</a>';

     createOption(name, distance, i);
     createMarker(latlng, name, address, town, postcode, link);
     bounds.extend(latlng);
   }
   map.fitBounds(bounds);
   locationSelect.style.visibility = "visible";
   locationSelect.onchange = function() {
     var markerNum = locationSelect.options[locationSelect.selectedIndex].value;
     google.maps.event.trigger(markers[markerNum], 'click');
   };
  });
 }

 function createMarker(latlng, name, address, town, postcode, link) {
  var html = "<b>" + town + "</b> <br/>" + address + "<br/>" + postcode + "<br/>" + link;
  var marker = new google.maps.Marker({
    map: map,
    position: latlng
  });
  google.maps.event.addListener(marker, 'click', function() {
    infoWindow.setContent(html);
    infoWindow.open(map, marker);
  });
  markers.push(marker);
}

 function createOption(name, distance, num) {
  var option = document.createElement("option");
  option.value = num;
  option.innerHTML = name + "(" + distance.toFixed(1) + ")";
  locationSelect.appendChild(option);
 }

 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.responseText, request.status);
    }
  };

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

 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');
  }
 }

 function doNothing() {}

//]]>
</script>


<script type="text/javascript">
    $(document).ready(function() {
        load();
    });
</script>

phpsqlsearch_genxml.php

<?php
$db_conn = mysql_connect('xxx.xxx.xx.xx', 'xxxxxxxx', 'xxxxxx') or die('error');
mysql_select_db('uk_db', $db_conn) or die(mysql_error());

// Get parameters from URL
$center_lat = $_GET["lat"];
$center_lng = $_GET["lng"];
$radius = $_GET["radius"];

if(!$_GET['zoom']) { 
    $_GET['zoom'] = 11; 
}

// Start XML file, create parent node
$dom = new DOMDocument("1.0");
$node = $dom->createElement("markers");
$parnode = $dom->appendChild($node);


// Select all the rows in the markers table
$query = 'SELECT address1, address2, address3, longitude, latitude, name, town, store_id, postcode, storenumber 
          FROM uk_store
          WHERE isActive=1 ';
if($_GET["region"] != '') {
    $query .= ' AND region = "' . $_GET["region"] . '"';
} else {
    $query .= ' AND region in("Scotland", "England", "Wales", "Northern Ireland") ';
}

// lets start to check what has been search on
if($_GET['postcode'] != '') {

  //lets make sure postcode only has numbers letter and spaces
  $searchparams .= 'postcode=' . $_GET['postcode'] . '&amp;';
  $postcode = $_GET['postcode'];
  $postcode = verifyInput($postcode);
  $query .= " AND postcode = '" . $postcode . "'";

}

if($_GET['town'] != '') {
    // make sure town only has letters or spaces.
    $searchparams .= 'town=' . $_GET['town'] . '&amp;';
    $town = $_GET['town']; 
    $town = verifyInput($town);
    $query .= " AND town = '" . $town . "'";
}

if($_GET['min_lat'] && $_GET['min_long'] && $_GET['max_lat'] && $_GET['max_long'] ) {
   $query .=   " AND latitude BETWEEN " . $_GET['min_lat'] . " AND " . $_GET['max_lat'] . " AND longitude BETWEEN " . $_GET['min_long'] . " AND " . $_GET['max_long'] ;
   $mapsearch = 1;
}

if(!($_GET['postcodeLat'] && $_GET['postcodeLong'])) {
    $query .= " ORDER BY Region, Town , Name "; 
}

$result = mysql_query($query);
if (!$result) {
  die("Invalid query: " . mysql_error());
}

header("Content-type: text/xml");

echo '<markers>';

if($_GET['postcodeLat'] && $_GET['postcodeLong'])
{
    $count = 0;

   // we need to sort the results by distance
    while ($row = @mysql_fetch_array($result, MYSQL_ASSOC))
    {
        $address = $row['address1'] . ' ' . $row['address2'] . ' ' . $row['address3'];
        $distance = distance($_GET['postcodeLat'], $_GET['postcodeLong'], $row['latitude'], $row['longitude']); 
        $row['distance'] = number_format($distance, 2);
        $row['fname'] = $row['town'] . '-' . $row['name'];
        $row['fname'] = str_replace("'",'', $row['fname']);
        $row['fname'] = ereg_replace(' ','-', $row['fname']); 
        $row['fname'] = ereg_replace('\/','-', $row['fname']);
        $row['fname'] = ereg_replace('\(','', $row['fname']);
        $row['fname'] = ereg_replace('\)','', $row['fname']);
        $row['fname'] = strtolower($row['fname']);
        //get distance and add to $row array
        $results[$distance.$row['id']] = $row;        
    } 

    ksort($results);

    foreach ($results as $key => $row) 
    {
      // ADD TO XML DOCUMENT NODE 
        $address = $row['address1'] . ' ' . $row['address2'] . ' ' . $row['address3'];  
        echo '<marker ';  
        echo 'name="' . parseToXML($row['name']) . '" ';  
        echo 'fname="' . parseToXML($row['fname']) . '" '; 
        echo 'town="' . parseToXML($row['town']) . '" ';  
        echo 'lat="' . $row['latitude'] . '" ';  
        echo 'lng="' . $row['longitude'] . '" ';  
        echo 'id="' . $row['store_id'] . '" ';  
        echo 'address="' . $address . '" '; 
        echo 'distance="' . $row['distance'] . '" '; 
        echo 'postcode="' . $row['postcode'] . '" ';
        echo 'storenumber="' . $row['storenumber'] . '" ';
        echo 'address1="' . parsetoXml($row['address1']). '" '; 
        echo 'address2="' . parsetoXml($row['address2']). '" '; 
        echo 'address3="' . parsetoXml($row['address3']). '" ';
        echo '/>';
    }

}
else
{
    // Iterate through the rows, printing XML nodes for each
    while ($row = @mysql_fetch_assoc($result))
    {
         $address = $row['address1'] . ' ' . $row['address2'] . ' ' . $row['address3'];
         $row['fname'] = $row['town'] . '-' . $row['name'];
         $row['fname'] = ereg_replace(' ','-', $row['fname']); 
         $row['fname'] = ereg_replace('\/','-', $row['fname']);
         $row['fname'] = ereg_replace('\(','', $row['fname']);
         $row['fname'] = ereg_replace('\)','', $row['fname']);

        // ADD TO XML DOCUMENT NODE  
        echo '<marker ';  
        echo 'name="' . parseToXML($row['name']) . '" ';
        echo 'fname="' . strtolower(parseToXML($row['fname'])) . '" '; 
        echo 'town="' . parseToXML($row['town']) . '" ';  
        echo 'lat="' . $row['latitude'] . '" ';  
        echo 'lng="' . $row['longitude'] . '" ';  
        echo 'id="' . $row['store_id'] . '" ';  
        echo 'isSurg="' . $row['isLaserSurgery'] . '" '; 
        echo 'isCons="' . $row['isLaserConsult'] . '" '; 
        echo 'address="' . parsetoXml($address). '" '; 
        echo 'address1="' . parsetoXml($row['address1']). '" '; 
        echo 'address2="' . parsetoXml($row['address2']). '" '; 
        echo 'address3="' . parsetoXml($row['address3']). '" '; 
        echo 'postcode="' . $row['postcode'] . '" '; 
        echo 'storenumber="' . $row['storenumber'] . '" ';
        echo '/>';
    }
}
// End XML file
echo '</markers>';


// make sure the data is xml friendly
function parseToXML($htmlStr) 
{ 
    $xmlStr=str_replace('<','&lt;',$htmlStr); 
    $xmlStr=str_replace('>','&gt;',$xmlStr); 
    $xmlStr=str_replace('"','&quot;',$xmlStr); 
    //$xmlStr=str_replace("'",'&#39;',$xmlStr); 
    $xmlStr=str_replace("&",'&amp;',$xmlStr); 
    return $xmlStr; 
}

// calculate the distance in miles or kms between any two points 
function distance($lat1, $lon1, $lat2, $lon2, $unit = '') { 
    $theta = $lon1 - $lon2; 
    $dist = sin(deg2rad($lat1)) * sin(deg2rad($lat2)) +  cos(deg2rad($lat1)) * cos(deg2rad($lat2)) * cos(deg2rad($theta)); 
    $dist = acos($dist); 
    $dist = rad2deg($dist); 
    $miles = $dist * 60 * 1.1515;
    if($unit != '')
    {
        $unit = strtoupper($unit);
    }

if ($unit == "K") {
    return ($miles * 1.609344); 
} else if ($unit == "N") {
  return ($miles * 0.8684);
} else {
    return $miles;
  }
} 

function VerifyInput ($input, $forceInt = false) { 

if (is_numeric($input)) { 
    return $input; 
} elseif (!$forceInt) { 

    if (get_magic_quotes_gpc() && trim(ini_get("magic_quotes_sybase")) == "") { 
        $input = stripslashes($input); 
        $input = str_replace("'", "", $input); 
        $input = str_replace("`", "", $input);
    } elseif (!get_magic_quotes_gpc()) { 
        $input = str_replace("'", "", $input);
        $input = str_replace("`", "", $input); 
    } 
    return $input; 
} elseif ($forceInt) { 
    return 0; 
} 
} 

?>

Apologies, that's a lot of pasting there but I thought it better to include everything rather than risk someone not being able to answer because there wasn't enough detail.

UPDATE

I have tried inserting this piece of code into the searchLocations function but it doesn't seem tochange the behaviour in anyway:

function searchLocations() {
 var address = document.getElementById("addressInput").value;
 var geocoder = new google.maps.Geocoder();
 geocoder.geocode({address: address}, function(results, status) {
   if (status == google.maps.GeocoderStatus.OK) {
    searchLocationsNear(results[0].geometry.location);
    /////////////// new code
    var myOptions = {
    zoom: 11,
    center: address.geometry.location,
    mapTypeId: google.maps.MapTypeId.TERRAIN
    }
    map = new google.maps.Map(document.getElementById("map"), myOptions);
    ////////////////

   } else {
     alert(address + ' not found');
   }
 });
}

Answer 1

Found the methods I was looking for in the documentation (surprise, surprise!)

Simply add these two lines under map.fitBounds(bounds); in the searchLocationsNear function:

   map.setZoom(11);
   map.setCenter(center);