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I have strange problem with rendering KML file in OpenLayers. It seems to be easy, but it's not. I've started with an example from here OpenLayers example . I wanted to add my own KML. It didn't work. I've created a local copy of the example with absolute urls, as follows:
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0">
<meta name="apple-mobile-web-app-capable" content="yes">
<link rel="stylesheet" href="http://openlayers.org/dev/theme/default/style.css" type="text/css" />
<link rel="stylesheet" href="http://openlayers.org/dev/examples/style.css" type="text/css" />
<script src="http://openlayers.org/dev/OpenLayers.js"></script>
<style type="text/css">
html, body {
height: 100%;
}
#map {
width: 100%;
height: 80%;
border: 1px solid black;
}
.olPopup p { margin:0px; font-size: .9em;}
.olPopup h2 { font-size:1.2em; }
</style>
<script type="text/javascript">
var lon = 5;
var lat = 40;
var zoom = 5;
var map, select;
function init(){
map = new OpenLayers.Map('map');
var wms = new OpenLayers.Layer.WMS(
"OpenLayers WMS",
"http://vmap0.tiles.osgeo.org/wms/vmap0",
{layers: 'basic'}
);
var sundials = new OpenLayers.Layer.Vector("KML", {
projection: map.displayProjection,
strategies: [new OpenLayers.Strategy.Fixed()],
protocol: new OpenLayers.Protocol.HTTP({
url: "http://openlayers.org/dev/examples/kml/sundials.kml",
format: new OpenLayers.Format.KML({
extractStyles: true,
extractAttributes: true
})
})
});
map.addLayers([wms, sundials]);
alert("deded");
select = new OpenLayers.Control.SelectFeature(sundials);
sundials.events.on({
"featureselected": onFeatureSelect,
"featureunselected": onFeatureUnselect
});
map.addControl(select);
select.activate();
map.zoomToExtent(new OpenLayers.Bounds(68.774414,11.381836,123.662109,34.628906));
}
function onPopupClose(evt) {
select.unselectAll();
}
function onFeatureSelect(event) {
var feature = event.feature;
// Since KML is user-generated, do naive protection against
// Javascript.
var content = "<h2>"+feature.attributes.name + "</h2>" + feature.attributes.description;
if (content.search("<script") != -1) {
content = "Content contained Javascript! Escaped content below.<br>" + content.replace(/</g, "<");
}
popup = new OpenLayers.Popup.FramedCloud("chicken",
feature.geometry.getBounds().getCenterLonLat(),
new OpenLayers.Size(100,100),
content,
null, true, onPopupClose);
feature.popup = popup;
map.addPopup(popup);
}
function onFeatureUnselect(event) {
var feature = event.feature;
if(feature.popup) {
map.removePopup(feature.popup);
feature.popup.destroy();
delete feature.popup;
}
}
</script>
</head>
<body onload="init()">
<h1 id="title">KML Layer Example</h1>
<div id="tags">
kml, popup, feature
</div>
<p id="shortdesc">
Demonstrates loading and displaying a KML file on top of a basemap.
</p>
<div id="map" class="smallmap"></div>
<div id="docs"></div>
</body>
</html>
It doesn;t render. I tried to change KML url to my local copy of sundial.kml (url: "http://openlayers.org/dev/examples/kml/sundials.kml", -> url: "/sundials.kml, and it didn't work either. I don't have Idea why.
Finally I want to add my own KML files, but they do not show either. What should I do?
Thanks in advance Rafal
529
The reason that your local copy of sundials.kml won't render is that you're using OpenLayers.Protocol.HTTP, which won't load an address of the kind file://directory/file.kml.
But I've no idea why your posted code doesn't render. I'm currently wrestling with the same problem. All I can tell you is what else doesn't work.
The Openlayers documentation explains how a GML layer can be used to load a KML layer. Unfortunately, the code snippet they give in the documentation doesn't match their actual example, which uses a Vector layer just like most of their other KML (and GML) examples.
I copied the example code anyway, but changed the Vector layer to var layer = new OpenLayers.Layer.GML("GML", "gml/polygon.xml");, as per the documentation. Then I made local copies of Openlayers.js, polygon.xml and the .css stylesheets, and changed the urls to point to my local copies. So everything is local.
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0">
<meta name="apple-mobile-web-app-capable" content="yes">
<title>GML Doesn't Render</title>
<link rel="stylesheet" href="defaultstyle.css" type="text/css">
<link rel="stylesheet" href="examplesstyle.css" type="text/css">
<script src="OpenLayers.js"></script>
<script type="text/javascript">
var map;
function init(){
map = new OpenLayers.Map('map');
var wms = new OpenLayers.Layer.WMS(
"OpenLayers WMS", "http://vmap0.tiles.osgeo.org/wms/vmap0",
{layers: 'basic'}
);
var layer = new OpenLayers.Layer.GML("GML", "gml/polygon.xml");
map.addLayers([wms, layer]);
map.zoomToExtent(new OpenLayers.Bounds(
-3.92, 44.34, 4.87, 49.55
));
}
</script>
</head>
<body onload="init()">
<div id="map" class="smallmap"></div>
</body>
</html>
It doesn't work.
I also tried the suggestion from the documentation:
var layer = new OpenLayers.Layer.GML("KML", "kml/lines.kml", {
format: OpenLayers.Format.KML,
formatOptions: {
'extractStyles': true
}
});
It doesn't work.
There is even a specific example of loading "locally stored GML vector data on a basemap". It uses the same code as the documentation, so, needless to say, it doesn't work. I can't hyperlink to it because I haven't enough reputation yet to make three hyperlinks, but you can find it if you search the examples for "GML".
Openlayers has a security feature to make it difficult to load data and javascript from wildly different locations (and a workaround called "proxyhost" if you really have to do this). But I can't see how that would get involved when all the urls point to the localhost.
Please be gentle, this is my first post!
EDIT: It turns out that a) it's a browser security feature, not OpenLayers, and b) it doesn't allow a script on the localhost to load any other file on the localhost, even if you're offline. Chrome/Chromium has a command-line parameter -allow-file-access-from-files. Using this parameter, the above examples work. Other workarounds (Google them) seem tricky.
109
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