@Override
    public void setDrivingMode(final boolean enabled) {
        mMap.viewport().setMapViewCenter(0f, enabled ? 0.5f : 0f);
    }
call this instead of VTM.layers().add so that we can keep track of layers added by the tile provider
main/src/main/java/cgeo/geocaching/unifiedmap/mapsforgevtm/MapsforgeVtmFragment.java