如何计算Android Geocoder结果的缩放级别

location_query

public void goToPlace(String location_query) {

    List<Address> addresses;
    Geocoder gc = new Geocoder(_ctx);

    addresses = gc.getFromLocationName(location_query, 1);
    if (addresses != null) {
        Address a = addresses.get(0);
        int lat = (int) (a.getLatitude() * 1E6);
        int lon = (int) (a.getLongitude() * 1E6);
        mapController.animateTo(new GeoPoint(lat, lon));
        mapController.setZoom(???);
    }
}