function hideMap(elementId)
{
  myElement = document.getElementById(elementId) ;
  myText = document.getElementById('hideMapText') ;
  if (myElement.style.opacity==""||myElement.style.opacity=="0.85") {
    myElement.style.opacity = 0 ;
    myText.innerHTML = 'Hide' ;
  }
  else {
    myElement.style.opacity = 0.85 ;
    myText.innerHTML = 'Show' ;
  } ;
}