Develop Reference

What do display custom icon for google map Marker?

currentPosition = new google.maps.LatLng(location.coords.latitude, location.coords.longitude);
var mapOptions = {
center: currentPosition,
zoom: 15,
mapTypeId: google.maps.MapTypeId.ROADMAP,
};
map = new google.maps.Map(document.getElementById("map-canvas"), mapOptions)
var home_marker = new google.maps.Marker({
position: currentPosition,
map: map,
icon: "../images/02_button_add.png"
});
Above is my code for google map API and trying to display a custom icon on map.
However, when I delete the icon file from folder. The map still show my icon.
Anyone knows what happen?

If you need to display another icon from same folder, you just change file name and hard reload your browser.
If you wish to display default google marker then remove icon property of marker from your code and hard reload your browser

Multiple instances of Google Maps on one page

I have a form that allows you to preview coordinates via a google map. The user can dynamically add multiple sets of coordinates to the form. The amount of coordinates are variable.
I loop through the variables with this code which I feel it has to do with loading multiple instances of google maps. The first map loads just fine, but the second map only loads one tile in the far left hand corner. IF I update the coordinates on the form, then all of the maps only show one tile in the far left hand corner.
while (tempClone != cloneCount) {
var lat_lng = new google.maps.LatLng(lat, lng);
options = {
zoom: 14,
center: lat_lng,
panControl: false,
zoomControl: false,
mapTypeId: google.maps.MapTypeId.TERRAIN
};
map[tempClone] = new google.maps.Map(document.getElementById("map"+tempClone), options);
var infowindow = new google.maps.InfoWindow({
content: inputBL[tempClone][0][1] + 'Entrance'
});
marker[tempClone] = new google.maps.Marker({
position: lat_lng,
map: map[tempClone],
title: inputBL[tempClone][0][1]
});
}
Thank you for any help!
Aaron

It almost looks like you're having trouble getting the map to resize. From what I recall this happens if the map container size changes. Can you try triggering a resize after showing the map?
google.maps.event.trigger(map, "resize");

Google map generating incorrectly

I have a program that takes in a zip code and makes a google map. The div that the map is set tohidden until the map is made. Once the map is made the div is set to display : block. The problem is that the first time the map is generated (and only the first time) it looks like this:
Once I hit the find a store button again it looks like this:
I have already tried to make a initial call to the map method (which I kept hidden until a real call is made) but this does not fix the issue. I don't want to show all my code (there is a lot) but here is how I make the map.
<div id = "map_canvas" style = " height: 300px; width: 300px;"></div>
//Creates a new center location for the google map
var latlng = new google.maps.LatLng(lat, lng);
//The options for the google map
var mapOptions = {
zoom: 7,
maxZoom: 12,
center: latlng,
mapTypeId: google.maps.MapTypeId.ROADMAP
};
//Creates the new map
map = new google.maps.Map(document.getElementById("map_canvas"), mapOptions);
Also note that both images below have the correct markers in the correct place.
Any suggestions?

this is a common problem. you need to trigger a map redraw after changing the container. most of the time this is caused by showing/hiding the div.
in v3 it's:
google.maps.event.trigger(map, 'resize')
in v2 it's:
map.checkResize()

It looks like when you initialize the map, it is completely zoomed out, which brings out the single 250x250 tile that google uses.

I would suspect that possibly an error is occurring on your first "Find Store" button click that might prevent the map creation code from being reached and executing properly.

Showing a specific location in gMAP

i want to show a map in a floating DIV. The thing i want to do is that i want to a specific location with it is first visible. for example: when it is visible i wnat to show banglore city. by default it show some of cities of USA i guess. Is it possible to do so....????

Yes, absolutely. You just have to set the map's center to the Lat Lng where you wish to initially show. For instance:
html (your DIV):
<div id='map_canvas'></div>
google map api v3 JavaScript run when onload:
var initCenter = new google.maps.LatLng(12.970214, 77.56029); //city of bangalor 12.970214, 77.56029
//create the google map and grabing the DIV
var map = new google.maps.Map(document.getElementById('map_canvas'), {
zoom: 10,
center: initCenter, //setting the city of bangalor as center point of your map
mapTypeId: google.maps.MapTypeId.ROADMAP
});
Here is the jsfiddle demo.

Google Map V3 not centering, displays only part of map

I'm developing a jQTouch-based app for the iPhone and part of it uses the Google Maps API (V3). I want to be able to pass the geolocation coordinates to the map and have it center the location with a marker. What I'm getting now is the map at the proper zoom level but the desired center-point appears in the upper-righthand corner. It's also showing only about a third of the map area (the rest is gray) and it behaves somewhat erratically when you pan or zoom. Here's the code:
var coords = { latitude : "35.510630", longitude : "-79.255374" };
var latlng = new google.maps.LatLng(coords.latitude, coords.longitude);
var myOptions = {
zoom: 12,
center: latlng,
mapTypeId: google.maps.MapTypeId.ROADMAP
};
var map = new google.maps.Map($("#map_canvas").get(0), myOptions);
var marker = new google.maps.Marker({
position: latlng,
map: map,
});
BTW: It looks and behaves the same on other platforms/browsers as well.
Thoughts?
Thanks in advance,
Mark
Added
Here's a link that'll show exactly what's happening:
Screen shot of iPhone emulator

I'm guessing you're using AJAX to display the map, or have the map hidden at some point and then display it based on an action?
In this case Google doesn't know the size of the map container and it will draw only part of the map, usually off-centered.
To fix this, resize the map, then re-center on your lat/lng. Something like this:
google.maps.event.trigger(map, 'resize');
// Recenter the map now that it's been redrawn
var reCenter = new google.maps.LatLng(yourLat, yourLng);
map.setCenter(reCenter);

The solution for getting the map renedered correctly is to execute your Maps-Code on pageAnimationEnd-Event of jQTouch.
Example within Page #div:
<div id="map_canvas" style="width:100%; height:100%; min-height:400px; background:#ccc;"></div>
<script type="text/javascript">
$('#map').bind('pageAnimationEnd', function() {
var mapOptions = {
zoom: 13,
disableDefaultUI: true,
mapTypeId: google.maps.MapTypeId.ROADMAP
};
var map = new google.maps.Map(document.getElementById('map_canvas'), mapOptions);
if(navigator.geolocation) {
navigator.geolocation.getCurrentPosition(function(position) {
var pos = new google.maps.LatLng(position.coords.latitude, position.coords.longitude)
var marker = new google.maps.Marker({
map: map,
draggable: false,
position: pos
});
map.setCenter(pos);
}, function() {
console.log('Device Environment Capable of Geolocation but not Available - Geolocation failed');
}
);
} else {
console.log('Device Environment Not Capable of Geolocation - Geolocation failed');
}
});
</script>
Though, i find myself having trouble to make the Map fullscreen-height. Any help in this case is appreciated. Note that im using DataZombies bars extension for fixed footer navigation.

see my answer on Google Maps API 3 & jQTouch
basically, your #map_canvas div is not visible at the time you're constructing the map as the div it's in has been hidden by jqtouch. the api can't deal with this and get's the size wrong.
would be much easier if gmaps v3 allowed setting explicit size in the constructor (as v2 did).
anyway, delay constucting map until 'pageAnimationEnd'.

Make sure you have set the width/height of the canvas absolutely (i.e.)
$("#map_canvas").width(window.innerWidth).height(window.innerHeight - $('.toolbar').height());
Of course that assumes you have the jqtouch toolbar up and running...

Had the same exact issue loading a map with directions after loading content with AJAX and showing and hiding the map-canvas div.
You have to trigger the resize event, like Brett DeWoody says, but I found that my global variable went out of scope and I had to refer to them, i.e. the google map variable, INSIDE my functions explicitly on the window object. Here's what I have inside my directionsService response:
if (status == google.maps.DirectionsStatus.OK) {
directionsDisplay.setDirections(response);
google.maps.event.trigger(window.map, 'resize');
}

Brett DeWoody's solution worked, but as I'm showing the map in modal the only solution for me was to add setTimeout like this:
setTimeout(function() {
google.maps.event.trigger(map, 'resize');
var reCenter = new google.maps.LatLng(lat, lng);
map.setCenter(reCenter);
}, 500);
After adding setTimeout the map renders and centers perfectly.