Center
setCenter(latlng)
 Description
 Sets the center location of the map.
 Parameter
 latlng (object)
 Example
  LatLng = {lat: 37.574674, lng: 126.958004};
 map.setCenter(LatLng);
 getCenter()
 Description
 Gets the center location you set.
 Return Value
 latlng (object)
 Example
 map.getCenter()
return : {lat: 37.574674, lng: 126.958004}