Issue with Postgress and Google Maps Markers - php

Question

I'm trying to draw points onto a map based on data in a Postgres DB, can anyone tell me why this won't work.. I'm scratching my head trying to figure it out.
I'm pulling data from a Postgres DB using this PHP code, which appears to be working just fine:
<?php
ini_set('memory_limit', '1024M');
// Connecting, selecting database
$dbconn = pg_connect(**MY LOGON DEETS**)
or die('Could not connect: ' . pg_last_error());
$lat1 = $_GET['lat1'];
$lat2 = $_GET['lat2'];
$lng1 = $_GET['lng1'];
$lng2 = $_GET['lng2'];
$pin_points = 'SELECT lat,lng,price,address_string FROM house_price_data_db.main where lat>=$1 and lat<=$2 and lng<=$3 and lng>=$4';
$result_pinpoints_points = pg_query_params($dbconn,$pin_points,array($lat1,$lat2,$lng1,$lng2)) or die('Query failed: ' . pg_last_error());
$pin_points_array = array();
while($r = pg_fetch_assoc($result_pinpoints_points)) {
$pin_points_array[] = $r;
}
header("Content-type: application/json" ); // set the header to json
echo(json_encode(array_values($pin_points_array), JSON_NUMERIC_CHECK)); // this will return json
pg_close($dbconn);
?>
To try and draw points on a map, using the code outlined below. I feel there's an error/issue with my Javascript, but I can't figure it out:
var lat1=55.55;
var lat2=56.05;
var lng1=8.00;
var lng2=8.45;
function setMarkers(){
if (window.XMLHttpRequest) {
// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp = new XMLHttpRequest();
} else { // code for IE6, IE5
xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange = function(){
if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
var pinpoints = JSON.parse(xmlhttp.responseText);
var marker;
var i=0;
var lat;
var lng;
var price;
var address;
var post_latlng;
var content;
for (i = 0;i<pinpoints.length;i++){
a=pinpoints[i];
lat=parseFloat(a["lat"]);
lng=parseFloat(a["lng"]);
price=parseFloat(a["price"]);
address=String(a["address_string"]);
post_latlng = new google.maps.LatLng(lat,lng);
content = "<b>Price:</b> " + price + '</br>' + "<b>Address:</b> " + address;
var marker = new google.maps.Marker({
map: map,
title: address,
position: post_latlng
});
map.setCenter(marker.getPosition());
var infowindow = new google.maps.InfoWindow();
google.maps.event.addListener(marker,'click', (function(marker,content,infowindow){
return function(){
infowindow.setContent(content);
infowindow.open(map,marker);
};
})(marker,content,infowindow));
}
}
}
xmlhttp.open("GET","pinpoints.php?lat1="+lat1+"&lat2="+lat2+"&lng1="+lng1+"&lng2="+lng2,false);
xmlhttp.send();
}
For some reason it won't work, I expect the function to call the PHP script, return an array and then use this array's contents and the Javscript function to draw markers on a map, that when clicked display some information. When I use Firebug I'm not getting any errors. Any suggestions on how to resolve this are more than welcome.

Answer 1

It turns out my code was working ok, but that the query I was sending to the database to test the function didn't have any returned rows.