Preload a Google Maps overlay - javascript

I'm trying to use a Google Map as a background, with a fixed overlay. Have a look-see.
You can see the problem — whilst it's loading, the text is unreadable. The overlay is loaded by Google's JS. How can I hide the map until the overlay has loaded? (Or a better solution?)

Actually, you can use JavaScript to make sure the map only displays when the overlay is loaded:
document.observe('dom:loaded', function()
{
if (GBrowserIsCompatible()) {
var overlaySrc = 'img/contact_map_overlay.png';
var preloadOverlay = new Image();
preloadOverlay.onload = function() {
var map = new GMap2(document.getElementById("map_canvas"));
map.setCenter(new GLatLng(-33.82568, 151.2180955505371), 14, G_PHYSICAL_MAP);
var mapTypeControl = new GMapTypeControl();
var topRight = new GControlPosition(G_ANCHOR_TOP_RIGHT, new GSize(80, 250));
map.addControl(new GSmallMapControl(), topRight);
var mapTarget = new GScreenOverlay(overlaySrc, new GScreenPoint(0.0, 0.0, 'fraction', 'fraction'), // screenXY
new GScreenPoint(0, 0), // overlayXY
new GScreenSize(1, 1, 'fraction', 'fraction') // size on screen
);
map.addOverlay(mapTarget);
var pin = new GIcon(G_DEFAULT_ICON);
pin.image = "img/pin.png";
pin.shadow = "no-shadow";
pin.iconSize = new GSize(34, 43);
markerOptions = {
icon: pin
};
var marker = new GMarker(new GLatLng(-33.82568, 151.240635), markerOptions);
map.addOverlay(marker);
}
preloadOverlay.src = overlaySrc;
}
});
Google simply displays the image from the server, so having it loaded into the cache before displaying the map will solve your problem.

I don't see any way in the v2 Api to either know when the overlay has loaded, or hide the map until it finishes the overlay.
The load() event fires before the overlays have finished loading. I notice the overlay is quite large at 684KB. A smaller overlay loads quicker.
You might also consider just putting a background image or something behind the contact us text which is being obscured (granted for only 5 seconds).

Related

creating multiple infowindows in Bing Maps v7 and presenting data specific to pin

I'm currently trying to learn the Bing Maps API and currently trying to build a map with multiple pins that can be hovered to reveal a info window with that pins data. At the moment I'm experiencing a few problems. If anyone could help with the following points that would be great:
When I mouseleave a pin the info window doesn't get removed?
How can I use the data I retrieve in the addPin() to populate the
required info window?
In createInfoBox() I want to hide any active info window when the
map gets moved but this seems to get triggered even if the map isn't
moved?
If there are any improvements i can make please let me know
jsfiddle: http://jsfiddle.net/kyllle/vpepD/23/ and JS below
JS
var dealerMap = {
createInfoBox: function(infobox) {
var instance = this,
pushpin = infobox;
// Now create infowindows
var NewWindow = new Microsoft.Maps.Infobox(pushpin.getLocation(), {
title: 'title',
offset: new Microsoft.Maps.Point(-3, pushpin.getHeight() - 5),
zIndex: 999,
visible: true
});
//Display infowindow
instance.displayInfoBox(NewWindow, pushpin);
//Hide infowindow if map is moved - currently gets run without moving map
//Microsoft.Maps.Events.addHandler(dealerMap.myMap, 'viewchange', instance.hideInfoBox(NewWindow));
},
displayInfoBox: function(infobox, pin) {
var instance = this;
//Show updated infowindow
dealerMap.myMap.entities.push(infobox);
//Mouse out handler to remove window
Microsoft.Maps.Events.addHandler(pin, 'mouseleave', function() {
instance.hideInfoBox(NewWindow);
});
},
hideInfoBox: function(infobox) {
var instance = this;
console.log('this was called');
dealerMap.myMap.entities.remove(infobox);
},
addPin: function() {
var instance = this;
//make $.ajax json call
var response = data.dummy;
//on success make each pin with returned data
for (var i = 0, len = response.length; i < len; i++) {
var responseItem = response[i],
pinLocation = new Microsoft.Maps.Location(responseItem.lat, responseItem.long);
//Create new pin
var NewPin = new Microsoft.Maps.Pushpin(pinLocation, {
icon: 'http://www.kylehouston.com/testing/sportscar_' + responseItem.id +'.png',
width: 32,
height: 37
});
//Push new pin onto map
this.myMap.entities.push(NewPin);
//Event handlers to show and hide requested infowindow information
Microsoft.Maps.Events.addHandler(NewPin, 'mouseover', function(e) {
console.log(this);
dealerMap.createInfoBox(e.target);
});
}
},
init: function() {
var instance = this;
var mapOptions = {
credentials: "AvGoKWSuMorGQb5h4UyyatCBGmGzSZe7-dWQMzXt4qqz6mV_WCC5m-paxvQhednd",
center: new Microsoft.Maps.Location(37.09024, -95.712891),
zoom: 5,
enableClickableLogo: false,
enableSearchLogo: false
}
dealerMap.myMap = new Microsoft.Maps.Map(document.getElementById('mapDiv'), mapOptions);
//now add some pins
instance.addPin();
}
}
dealerMap.init();
});
I highly recommend only showing one infobox at a time on the map. Showing multiple infoboxes can crowd the map and make for a bad user experience. It also uses up a lot more resources. A better approach is to create a single infobox and reuse it for each pushpin as you want to display content. I wrote a blog post that shows how to do this here: http://rbrundritt.wordpress.com/2011/10/13/multiple-pushpins-and-infoboxes-in-bing-maps-v7/

how to take snapshot of google map with polyline and openInfoWindowHtml

I'm working on functionality to take snapshot of google map with polylines and open popup window on polyline click on google map.
The snapshot of google map with polylines is working
but it will not able to take snapshot open popup window on polyline.
polyline are showing on sanpshot picture but info window are not showing .
Here is code to take snapshot.
This code is to initialize the code control on javascript onload :
var snapShotControlOptions = { hidden: true };
snapShotControlOptions.buttonLabelHtml="<snap id='snap' style='display:none' >snap</span>"
snapShotControl = new SnapShotControl(snapShotControlOptions);
map.addControl(snapShotControl);
here is the method take snap to take the sanp shot of google map .
function takeSnap() {
//static map size
var sizeStr = "640x640";
var imgSize = "";
if (sizeStr != "") {
var sizeArray = sizeStr.split("x");
imgSize = new GSize(sizeArray[0], sizeArray[1]);
}
snapShotControl.setMapSize(imgSize);
var format = "jpg";
snapShotControl.setFormat(format);
var url = snapShotControl.getImage();
// document.getElementById("snapshot_canvas").src = url;
SaveImage(url);
//
}
//this will add polyline overlay to draw line on google map with different color of polyline on google map .
var polyline = directionsArray[num].getPolyline();
polyline.setStrokeStyle({ color: streetColor, weight: 3, opacity: 0.7 });
polyline.ssColor=streetColor;
map.addOverlay(polyline);
///this code will open the pop info window on polyline those polyline created on google map
and problem is their these pop window not included on sanpshot when i take sanpshot of google map.
var MousePoint = "";
var marker;
GEvent.addListener(map, "mousemove", function (point) {
MousePoint = new GLatLng(point.lat(), point.lng());
});
GEvent.addListener(polyline, "click", function () {
map.openInfoWindowHtml(MousePoint, headMarkerHtml);
});
GEvent.addListener(polyline, "mouseout", function () {
// map.closeInfoWindow();
});
can you please tell who i pass popup window in polyline overlay .
i have use javascript file snapshotcontrol.js to take the snapshot.
from the snapshotcontrol source
This library makes it easy to generate an image "snapshot" of your
interactive map, using the Google Static Maps API.
Static maps doesn't support info windows or anything like adding custom text to the map
https://developers.google.com/maps/documentation/staticmaps/index
You could draw the map on a canvas within the browser then
draw the info window on top of that using this http://html2canvas.hertzen.com/
and then download the canvas content

Dynamic rectangles in Google Maps

First I'm pretty new to Javascript, so sorry if my question comes across poorly.
I'm creating an application in Flash to help users calculate their electrical costs. Then I'm taking this figure and write it to an xml file.
Now I'm looking to open a webpage and show a google map, and there is a rectangle drawn over the map which is generated dynamically from the number generated earlier and stored in the xml file.
I'm completely lost as to places to turn on how to achieve this. I've gotten my map on to my page, and it scales 100% as I want it to, but I can't figure out the dynamic rectangle part at all. Any ideas or pointers in the right direction greatly appreciated.
In this latest version, the XML file
<countries>
<country name="USA" lat="40.0" lng="-100.0" width="30.0"/>
<country name="France" lat="46.6" lng="2.7" width="10"/>
<country name="Germany" lat="51.1" lng="10.1" width="20"/>
</countries>
is loaded as soon as the map tiles finish loading. I could not get the getProjection to be called correctly if I did not wait for tile loading to finish. The docs state that getting the projection needs the map to be initialized, and recommends listening for projection_changed. Both ways work yet I still feel listening to tiles_loaded is safer and if something goes wrong with the xml loading it will get called again if the map is zoomed or panned a noticeable amount.
var map;
var xmlLoaded = false;
function initialize() {
var mapOptions = { center: new google.maps.LatLng(30.0, 0.0), zoom: 2,
mapTypeId: google.maps.MapTypeId.ROADMAP };
map = new google.maps.Map(document.getElementById("map_canvas"), mapOptions);
google.maps.event.addListener(map, 'tilesloaded', loadData);
}
function loadData() {
if(!xmlLoaded) {
$.ajax({
type: "GET",
url: "co2data.xml",
dataType: "xml",
success: function(xml) {
var countries = xml.documentElement.getElementsByTagName("country");
for(var i = 0, country; country = countries[i]; i++) {
var name = country.getAttribute("name");
var lat = parseFloat(country.getAttribute("lat"));
var lng = parseFloat(country.getAttribute("lng"));
var point = map.getProjection().fromLatLngToPoint(new google.maps.LatLng(lat,lng));
// width is really an arbitrary unit, relative to CO2 tonnage.
// equals the side of the drawn square.
// it is measured in google maps points units.
var width = parseFloat(country.getAttribute("width"));
makeCO2Rect(name, point, width);
}
xmlLoaded = true;
}
});
}
}
The rectangle is defined by width in points (the whole world is 256x256 points), so some conversion is needed when assigning their centers to the more conventional LatLng.
function rectParamsToBounds(point, width) {
var ctrX = point.x;
var ctrY = point.y;
var swX = ctrX - (width/2);
var swY = ctrY - (width/2);
var neX = ctrX + (width/2);
var neY = ctrY + (width/2);
return new google.maps.LatLngBounds(
map.getProjection().fromPointToLatLng(new google.maps.Point(swX, swY)),
map.getProjection().fromPointToLatLng(new google.maps.Point(neX, neY)));
}
Finally, a rectangle is created with a country name that goes into a MarkerWithLabel (using v1.1.5 here, you can hotlink to http://google-maps-utility-library-v3.googlecode.com/svn/tags/markerwithlabel/1.1.5/src/markerwithlabel_packed.js though I prefer saving a local copy)
Since dragging a rectangle appears impossible, a marker in its center works as a handle. When it's dragged, the associated rectangle moves with it.
function makeCO2Rect(name, point, width) {
var rect = new google.maps.Rectangle({
map: map,
bounds: rectParamsToBounds(point, width)
});
var marker = new MarkerWithLabel({
map: map,
position: map.getProjection().fromPointToLatLng(new google.maps.Point(point.x, point.y)),
draggable: true,
raiseOnDrag: false,
labelContent: name,
labelAnchor: new google.maps.Point(30, 0),
labelClass: "labels", // the CSS class for the label
labelStyle: {opacity: 1.0}
});
google.maps.event.addListener(marker, 'drag', function(event) {
var newLatLng = event.latLng;
var newPoint = map.getProjection().fromLatLngToPoint(newLatLng);
rect.setBounds(rectParamsToBounds(newPoint, width));
});
}
google.maps.event.addDomListener(window, 'load', initialize);
Styling the labels need to be done both in the .labels CSS class and the constructor, and rectangles have options like stroke color, thickness, opacity, and fill color.
If you just want to place a rectangular shape on the map, you can create a google.maps.Rectangleapi-doc. If you want to create a rectangular label on the map, you may be more interested in the InfoBox Utility Librarywiki-page.

Google Maps: remember id of marker with open info window

I have a Google map that is showing a number of markers. When the user moves the map, the markers are redrawn for the new boundaries, using the code below:
GEvent.addListener(map, "moveend", function() {
var newBounds = map.getBounds();
for(var i = 0; i < places_json.places.length ; i++) {
// if marker is within the new bounds then do...
var latlng = new GLatLng(places_json.places[i].lat, places_json.places[i].lon);
var html = "blah";
var marker = createMarker(latlng, html);
map.addOverlay(marker);
}
});
My question is simple. If the user has clicked on a marker so that it is showing an open info window, currently when the boundaries are redrawn the info window is closed, because the marker is added again from scratch. How can I prevent this?
It is not ideal, because often the boundaries are redrawn when the user clicks on a marker and the map moves to display the info window - so the info window appears and then disappears again :)
I guess there are a couple of possible ways:
remember which marker has an open info window, and open it again when the markers are redrawn
don't actually re-add the marker with an open info window, just leave it there
However, both require the marker with an open window to have some kind of ID number, and I don't know that this is actually the case in the Google Maps API. Anyone?
----------UPDATE------------------
I've tried doing it by loading the markers into an initial array, as suggested. This loads OK, but the page crashes after the map is dragged.
<script type="text/javascript" src="{{ MEDIA_URL }}js/markerclusterer.js"></script>
<script type='text/javascript'>
function createMarker(point,html, hideMarker) {
//alert('createMarker');
var icon = new GIcon(G_DEFAULT_ICON);
icon.image = "http://chart.apis.google.com/chart?cht=mm&chs=24x32&chco=FFFFFF,008CFF,000000&ext=.png";
var tmpMarker = new GMarker(point, {icon: icon, hide: hideMarker});
GEvent.addListener(tmpMarker, "click", function() {
tmpMarker.openInfoWindowHtml(html);
});
return tmpMarker;
}
var map = new GMap2(document.getElementById("map_canvas"));
map.addControl(new GSmallMapControl());
var mapLatLng = new GLatLng({{ place.lat }}, {{ place.lon }});
map.setCenter(mapLatLng, 12);
map.addOverlay(new GMarker(mapLatLng));
// load initial markers from json array
var markers = [];
var initialBounds = map.getBounds();
for(var i = 0; i < places_json.places.length ; i++) {
var latlng = new GLatLng(places_json.places[i].lat, places_json.places[i].lon);
var html = "<strong><a href='/place/" + places_json.places[i].placesidx + "/" + places_json.places[i].area + "'>" + places_json.places[i].area + "</a></strong><br/>" + places_json.places[i].county;
var hideMarker = true;
if((initialBounds.getSouthWest().lat() < places_json.places[i].lat) && (places_json.places[i].lat < initialBounds.getNorthEast().lat()) && (initialBounds.getSouthWest().lng() < places_json.places[i].lon) && (places_json.places[i].lon < initialBounds.getNorthEast().lng()) && (places_json.places[i].placesidx != {{ place.placesidx }})) {
hideMarker = false;
}
var marker = createMarker(latlng, html, hideMarker);
markers.push(marker);
}
var markerCluster = new MarkerClusterer(map, markers, {maxZoom: 11});
</script>
You should probably create all your markers at an initial stage with your createMarker() method, and store the returned GMarker objects inside an array. Make sure to set the hide: true property in GMarkerOptions when you create your markers, so that they would be created as hidden by default.
Then instead of iterating through places_json.places, you could iterate through your new GMarker array. You would be able to get the coordinates of each marker with the GMarker.getLatLng() method, with which to check if each marker lies within the bounds.
Finally simply call GMarker.show() for markers that lie within the bounds, or GMarker.hide() to hide them.
You would eliminate the expensive destruction/creation of markers on each map movement. As a positive-side effect, this will also solve your GInfoWindow problem.
If you're using that many markers, make sure you use GMarkerManager. It's designed for many markers, with only a few visible at once.
http://mapki.com/wiki/Marker_Optimization_Tips

Google Maps - Custom Icon & Popup overlay issues

I've looked at as many examples as I could find, and they all show me the same thing. I can't figure out what I'm doing wrong. I'm using a custom icon, placing it on the map, and adding a popup overlay to it. The custom icon will display, but the popup won't. If I don't use a custom icon, the popup and icon work fine.
function initialize() {
if (GBrowserIsCompatible()) {
var map = new GMap2(document.getElementById("map_canvas"));
map.setCenter(new GLatLng(43.220689, -87.974396), 11);
var pin1 = "http://chart.apis.google.com/chart?chst=d_map_xpin_letter&chld=pin_star|1|FF0000|000000|00E5FF";
var shadow = "http://www.google.com/mapfiles/shadow50.png";
var Icon1 = new GIcon();
Icon1.image = pin1;
Icon1.shadow = shadow;
Icon1.iconAnchor = new GPoint(6, 20);
function createMarker(point, html) {
var marker = new GMarker(point,{clickable:true, icon:Icon1});
GEvent.addListener(marker, "click", function() { marker.openInfoWindowHtml(html); });
return marker;
}
var point = new GLatLng(43.308926, -87.961113);
var html = "Some stuff.";
var marker = createMarker(point, html);
map.addOverlay(marker);
map.setUIToDefault();
}
}
Please help! I have no idea what else to look at. Something is causing the popup to break when the custom icon is there. But the icon shows fine, so it's formatted properly.
Thanks

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