Reverse Geocode On Google Maps api v3 - php

Question

I wonder whether someone may be able to help me please.
I using the code shown below to correctly plot markers retrieved from a MySQL database on a Google Map.
<script type="text/javascript">
//Sample code written by August Li
var icon = new google.maps.MarkerImage("images/location-marker-2.png")
new google.maps.Point(16, 32);
var center = null;
var map = null;
var bounds = new google.maps.LatLngBounds();
function addMarker(lat, lng, info) {
var pt = new google.maps.LatLng(lat, lng);
bounds.extend(pt);
var marker = new google.maps.Marker({
position: pt,
icon: icon,
map: map
});
}
function initMap() {
map = new google.maps.Map(document.getElementById("gmaps-canvas"), {
center: new google.maps.LatLng(0, 0),
zoom: 6,
scrollwheel: true,
draggable: true,
mapTypeId: google.maps.MapTypeId.SATELLITE
});
<?php
include("admin/link.php");
include("admin/opendb.php");
$query = mysql_query("SELECT * FROM `detectinglocations` WHERE `locationid` = '$lid'");
while ($row = mysql_fetch_array($query)){
$locationname=$row['locationname'];
$osgb36lat=$row['osgb36lat'];
$osgb36lon=$row['osgb36lon'];
echo ("addMarker($osgb36lat, $osgb36lon,'<b>$locationname</b><br/>');\n");
}
mysql_close($connect);
?>
center = bounds.getCenter();
map.fitBounds(bounds);
}
</script>
What I'm now trying to do is add further functionality that allows users to also click on the map to plot new markers, in essence using the pre-existing marker from the database as a point to work from, performing a reverse geocode.
I've been researching this for a number of days now and I've tried to implement a whole host of tutorials, but I just can't seem to get both parts of the functionality working.
I do know that to enable a on-click event I need to incorporate something along the lines of:
google.maps.event.addListener(map, 'click', function(event) {
marker.setPosition(event.latLng)
geocode_lookup( 'latLng', event.latLng );
});
}
but I must admit I'm a little unsure about what else I need to incorporate.
I just wondered whether someone may be able to take a look at this please, and I'd be very grateful if someone could show me where I've gone wrong.
Many thanks and kind regards

Answer 1

I wrote a separate maps page with just click-to-reverse-geocode functionality
http://jsfiddle.net/ZDQeM/
The address details are confusing to work with, I think. The results are an array, at different levels of precision, one might include the county, another the state, another the street address. Generally I only use results[0]. The details are in the docs: https://developers.google.com/maps/documentation/javascript/geocoding#GeocodingResponses
If you need specific information the sure way to obtain it is iterate through the whole results array until you find what you need (types[] containing postal_code, for example).
google.maps.event.addListener(map, 'click', function(event) {
userMarker = new google.maps.Marker({
map: map,
position: event.latLng
});
geocoder.geocode({'latLng': event.latLng}, function(results, status) {
if(status == google.maps.GeocoderStatus.OK) {
if (results[0]) {
alert(results[0].formatted_address);
}
else {
alert("No results");
}
}
else {
alert("Geocoding unsuccessful: Status " + status);
}
});
});
Where in your code?
<script type="text/javascript">
//Sample code written by August Li
var icon = new google.maps.MarkerImage("images/location-marker-2.png")
new google.maps.Point(16, 32);
var center = null;
var map = null;
var bounds = new google.maps.LatLngBounds();
function addMarker(lat, lng, info) {
var pt = new google.maps.LatLng(lat, lng);
bounds.extend(pt);
var marker = new google.maps.Marker({
position: pt,
icon: icon,
map: map
});
}
function initMap() {
map = new google.maps.Map(document.getElementById("gmaps-canvas"), {
center: new google.maps.LatLng(0, 0),
zoom: 6,
scrollwheel: true,
draggable: true,
mapTypeId: google.maps.MapTypeId.SATELLITE
});
<?php
include("admin/link.php");
include("admin/opendb.php");
$query = mysql_query("SELECT * FROM `detectinglocations` WHERE `locationid` = '$lid'");
while ($row = mysql_fetch_array($query)){
$locationname=$row['locationname'];
$osgb36lat=$row['osgb36lat'];
$osgb36lon=$row['osgb36lon'];
echo ("addMarker($osgb36lat, $osgb36lon,'<b>$locationname</b><br/>');\n");
}
mysql_close($connect);
?>
center = bounds.getCenter();
map.fitBounds(bounds);
var geocoder = new google.maps.Geocoder();
google.maps.event.addListener(map, 'click', function(event) {
var userMarker = new google.maps.Marker({
map: map,
position: event.latLng
});
geocoder.geocode({'latLng': event.latLng}, function(results, status) {
if(status == google.maps.GeocoderStatus.OK) {
if (results[0]) {
alert(results[0].formatted_address);
}
else {
alert("No results");
}
}
else {
alert("Geocoding unsuccessful: Status " + status);
}
});
});
}
</script>