That did it!
That and removing the reference to the projection. Thanks to Dave
Winfield's help, I realised that EPSG:27700 is not, in fact, the OS
grid I was using. Since it's a simple cartesian grid, though, I just
removed all reference to projection but kept the maxExtents and that
worked fine. If you visit the site again, you'll see the map
complete with markers (nevermind the few outliers in the sea, though).
http://www.thomasav.com/countiesimage.html
Thanks to everyone!
-- Anthony
On Jul 23, 2009, at 10:20 PM, Arnd Wippermann wrote:
Hi,
insert maxResolution to your options2, then it should work.
var options2 = {numZoomLevels: 3, projection: "EPSG:27700",
isBaseLayer: true, maxResolution:1000};
Arnd
Von: [email protected] [mailto:users-
[email protected]] Im Auftrag von Anthony Masinton
Gesendet: Donnerstag, 23. Juli 2009 16:07
An: [email protected]
Betreff: [OpenLayers-Users] Map Image Layer
Good afternoon,
I've been beating my head against this all day so I'll ask for
wisdom from the group.
I'm trying to create a simple map of England with the outlines of
all of the counties. I have an image which showing this, which I
would like to use as my basemap for an eventual marker overlay.
Because all of my marker coordinates are in Ordnance Survey British
National Grid format (x and y are six digit numbers), I have
georeferenced this image in ArcGIS to get the image bounds. I have
then noted these bounds in the extents of the image.
The map is here: http://www.thomasav.com/countiesimage.html
As you can see, this is simply the image layer example but with the
WMS layer removed and the properties of the image layer altered to
suit my image.
As you can alos see, nothing happens when the page loads. The image
area is blank. Firebug tells me that map is undefined. I can't
figure out what this means, as the only thing I've changed is image
layer itself.
The code for the page follows, as you can see, I've tried a few
things to fix this (commented out) but to no avail.
Many many thanks for your time and comments.
-- Anthony
Code:
<html xmlns="http://www.w3.org/1999/xhtml";>
<head>
<title>OpenLayers Image Layer Example</title>
<link rel="stylesheet" href="/theme/default/style.css"
type="text/css" />
<link rel="stylesheet" href="style.css" type="text/css" />
<style type="text/css">
p.caption {
width: 512px;
}
</style>
<script src="/lib/OpenLayers.js"></script>
<script type="text/javascript">
var map;
function init(){
// var options = {
// maxExtent: new OpenLayers.Bounds
(125755.604,922.206,662492.41,661558.365),
// var center = bounds.getCenterLonLat(400000, 400000),
// maxResolution: 156543,
// units: 'm',
// projection: "EPSG:27700"
// isBaseLayer: true
// };
map = new OpenLayers.Map ("map");
var options2 = {numZoomLevels: 3, projection: "EPSG:
27700", isBaseLayer: true};
var graphic = new OpenLayers.Layer.Image(
'Counties',
'http://www.thomasav.com/england.jpg',
new OpenLayers.Bounds
(125755.604,922.206,662492.41,661558.365),
new OpenLayers.Size(2231, 2746),
options2);
map.addLayers([graphic]);
map.addControl(new OpenLayers.Control.LayerSwitcher());
map.zoomToMaxExtent();
}
</script>
</head>
<body onload="init()">
<h1 id="title">Image Layer Example</h1>
<div id="tags"></div>
<p id="shortdesc">
Demonstrate a single non-tiled image as a selectable base
layer.
</p>
<div style="width:100%; height:100%" id="map"></div>
<div id="docs">
<p class="caption">
The "City Lights" layer above is created from a single
web accessible
image. If you construct it without any resolution
related options,
the layer will be given a single resolution based on
the extent/size.
Otherwise, it behaves much like a regular layer. This
is primarily
intended to be used in an overview map - where another
layer type
might not make a good overview.
</p>
</div>
</body>
</html>
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