a list of zoom/pan options (see
http://leafletjs.com/reference.html#map-zoompanoptions)
lng1, lat1, lng2, lat2
the coordinates of the map bounds
Value
The modified map widget.
Functions
setView: Set the view of the map (center and zoom level)
fitBounds: Set the bounds of a map
setMaxBounds: Restricts the map view to the given bounds
clearBounds: Clear the bounds of a map, and the bounds will be
automatically determined from latitudes and longitudes of the map elements
if available (otherwise the full world view is used)