The second argument to map.setCenter is a zoom.
var map = new OpenLayers.Map("mapdiv");
// add layers here
map.setCenter(new OpenLayers.LonLat(yourlon, yourlat), 5);
If you want something more complex than that, you're probably going to need to share more details about what your map and setup currently look like. (Projection, base layer, etc.)
you can catch your opened(active) popup with this way:
map.popups[a]
you can change so update its content:
map.popups[a].contentHTML = 'Test Content';
map.popups[a].redraw();
or
map.popups[a].setContentHTML = 'Test Content'
you can show or hide your popup:
map.popups[a].show();
map.popups[a].hide();
you can update position of your popup:
map.popups[a].lonlat.lon = 10;
map.popups[a].lonlat.lat = 10;
map.popups[a].updatePosition();
for openlayers cluster you should check out Cluster Strategy Example here. Only one thing you should do is that define fillColor or externalGraphic for your cluster.
var style = new OpenLayers.Style({
pointRadius: "${radius}",
fillColor: "${getColor}",
fillOpacity: 0.8,
strokeColor: "#cc6633",
strokeWidth: 2,
strokeOpacity: 0.8
}, {
context: {
radius: function(feature) {
return Math.min(feature.attributes.count, 7) + 3;
},
getColor: function(feature) {
return // Your color selection logic;
}
}
});
As the last question, i dont understand very well what you want? but try to use removeFeatures instead of destroyFeatures....
i hope it helps you...
Best Answer
A brute force and simple solution can be removing the layer from the map and, after that, adding a new one with the same name which, besides, would use a different style map and would not feature the cluster strategy.