Passing Map Location information from PHP to javascript for use with Google maps v3 api

Question

I have a bunch of latitude & longitude markers stored in MySQL which I can retrieve simply with PHP. I interact with the Google maps API v3 with Javascript and load several markers in an array as a dummy, each one has a infowindow as well.

What would people recommend as the best method of handing the data in MySQL to a javascript object/array for use with the google maps api v3.

Answer 1

Get the values from DB, by using PHP while loop and store the values in a variable as below

$location .= '['. $row['latitude'] . ',' . $row['longitude'] . ',"' . $row['city'] . '","' . $row['state'] . '"],' ;

In Javascript, assign the PHP variable to a Javascript variable as below.

var locations = [<?php echo isset($location)?$location:''; ?>];
var len = locations.length;
for (i = 0; i < len; i++) {  
   var image = 'GIVE HERE THE PATH OF IMAGE';
   marker = new google.maps.Marker({
     position: new google.maps.LatLng(locations[i][1], locations[i][2]),
     map: map,
     icon: image
   });
   google.maps.event.addListener(marker, 'mouseover', (function(marker, i) {
     return function() {              
    infowindow.setContent(content);
    infowindow.open(map, marker);
 }
   })(marker, i));
}

The above code will give multiple markers and as well as infobox for each marker in the map.

Answer 2

If you have a PhP array containing a lot of markers, for example:

Array
(
    [0] => Array
           (
           ["lat"]=> <value>
           ["lng"]=> <value>
           ["info"]=> <value>
           )
    [1] => Array
           (
           ["lat"]=> <value>
           ["lng"]=> <value>
           ["info"]=> <value>
           )
    [2] => ...
    [3] => ...
)

using JSON is a good solution as :

1. it will save you the trouble of escaping the values stored in it
2. You can easily retrieve the same data structure in javascript (using JSON.parse() if you need to) and use it create your markers.

To convert your array to JSON from PhP:

json_encode($myMarkersArray, JSON_NUMERIC_CHECK)