function showMap(zoom) {
    //set up map
    //geotags for glasgow G2 geo:lat=55.8645 geo:long=-4.2641
    var point = new GPoint(-4.2641,55.8645);
    var map = new GMap(document.getElementById("map"));
    map.addControl(new GSmallMapControl());
    map.centerAndZoom(point,zoom);
    map.addOverlay(new GMarker(new GPoint(-4.2641,55.8645)));
}