function getMarker(latlng, markerOptions, description) {
    var marker = new GMarker(latlng, markerOptions);
    GEvent.addListener(marker, "click", function() { map.openInfoWindowHtml(latlng, description); });
    return marker;
}


function refreshMap() {
    markerPosition = 0;
    
    if (markerCluster != null) {
        markerCluster.clearMarkers();
    }
    
    refreshMarkerArray();
    var mcOptions = { gridSize: 30, maxZoom: 15};
    markerCluster = new MarkerClusterer(map, markerArray, mcOptions);
}


function refreshMarkerArray() {
    agencyNumber = 0;
    markerArray = [];
    
    for (var i = 0; i < mO.length; i++) {
            var marker = mO[i]["marker"];
            var showMarker = true;

            if (showMarker) {
                markerArray.push(marker);
                agencyNumber++;
            }
    }
 
}