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var map, layer, overlay;
var projectionOptions = {
'EPSG:3574': {
projection: new OpenLayers.Projection('EPSG:3574'),
units: 'm',
maxExtent: new OpenLayers.Bounds(-5505054, -5505054, 5505054, 5505054),
maxResolution: 5505054 / 128,
numZoomLevels: 18
},
'EPSG:3576': {
projection: new OpenLayers.Projection('EPSG:3576'),
units: 'm',
maxExtent: new OpenLayers.Bounds(-5505054, -5505054, 5505054, 5505054),
maxResolution: 5505054 / 128,
numZoomLevels: 18
},
'EPSG:3571': {
projection: new OpenLayers.Projection('EPSG:3571'),
units: 'm',
maxExtent: new OpenLayers.Bounds(-5505054, -5505054, 5505054, 5505054),
maxResolution: 5505054 / 128,
numZoomLevels: 18
},
'EPSG:3573': {
projection: new OpenLayers.Projection('EPSG:3573'),
units: 'm',
maxExtent: new OpenLayers.Bounds(-5505054, -5505054, 5505054, 5505054),
maxResolution: 5505054 / 128,
numZoomLevels: 18
}
};
function setProjection() {
projCode = this.innerHTML;
var oldExtent = map.getExtent();
var oldCenter = map.getCenter();
var oldProjection = map.getProjectionObject();
// map projection is controlled by the base layer
map.baseLayer.addOptions(projectionOptions[projCode]);
// with the base layer updated, the map has the new projection now
var newProjection = map.getProjectionObject();
// transform the center of the old projection, not the extent
map.setCenter(
oldCenter.transform(oldProjection, newProjection,
map.getZoomForExtent(oldExtent.transform(oldProjection, newProjection))
));
for (var i=map.layers.length-1; i>=0; --i) {
// update grid settings
map.layers[i].addOptions(projectionOptions[projCode]);
// redraw layer - just in case center and zoom are the same in old and
// new projection
map.layers[i].redraw();
}
}
function init() {
map = new OpenLayers.Map('map');
layer = new OpenLayers.Layer.WMS(
'world',
'http://v2.suite.opengeo.org/geoserver/wms',
{layers: 'world', version: '1.1.1'},
projectionOptions['EPSG:3574']
);
overlay = new OpenLayers.Layer.WMS(
'world',
'http://v2.suite.opengeo.org/geoserver/wms',
{transparent: 'true', layers: 'world:borders', styles: 'line'},
projectionOptions['EPSG:3574']
);
overlay.isBaseLayer = false;
map.addLayers([layer, overlay]);
map.zoomToMaxExtent();
// add behaviour to dom elements
document.getElementById('epsg3574').onclick = setProjection;
document.getElementById('epsg3576').onclick = setProjection;
document.getElementById('epsg3571').onclick = setProjection;
document.getElementById('epsg3573').onclick = setProjection;
}
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