function mapClick () {

var objSelect = document.getElementById('aid');

switch ( objSelect.options[objSelect.selectedIndex].value ) {

 case '2027 : window.location.href='si.cmsx?itemID=1390&mapLon=-0.4545&mapLat=51.0238&mapZoom=4'; break

 case '6018' : window.location.href='si.cmsx?itemID=1390&mapLon=-0.3274&mapLat=51.0637&mapZoom=4'; break

 case '2029' : window.location.href='si.cmsx?itemID=1390&mapLon=-0.3508758544921875&mapLat=51.02390535577586&mapZoom=4'; break

 case '8899' : window.location.href='si.cmsx?itemID=1390&mapLon=-0.45867919921875&mapLat=50.915047654938746&mapZoom=4'; break

 default : window.location.href='si.cmsx?itemID=1390';

 }

}