Center google map whilst maintaining bounds

centerOnLatLng

 function centerOnLatLng(center) {
	var map = this.map,
		bounds = map.getBounds(),
		ne = bounds.getNorthEast(),
		sw = bounds.getSouthWest(),
		neLatDif, swLatDif,
		neLonDif, swLonDif,
		newBoundary = new google.maps.LatLngBounds();

	//Lat
	neLatDif = center.lat() - ne.lat();
	swLatDif = center.lat() - sw.lat();			

	//if the sw is closer than ne
	if (Math.abs(swLatDif) < Math.abs(neLatDif)) {
		//extend the sw lat by the diference
		sw = new google.maps.LatLng(sw.lat() + (neLatDif + swLatDif), sw.lng());
	}
	else {
		//extend the ne lat by the diference
		ne = new google.maps.LatLng(ne.lat() + (swLatDif + neLatDif), ne.lng());
	}			

	//Lng
	neLonDif = center.lng() - ne.lng();
	swLonDif = center.lng() - sw.lng();

	//if the sw is closer than ne
	if (Math.abs(swLonDif) < Math.abs(neLonDif)) {
		//extend the sw lng by the diference
		sw = new google.maps.LatLng(sw.lat(), sw.lng() + (neLonDif + swLonDif));
	}
	else {
		//extend the ne lng by the diference
		ne = new google.maps.LatLng(ne.lat(), ne.lng() + (swLonDif + neLonDif));
	}

	//extend to these new boundaries
	newBoundary.extend(sw);
	newBoundary.extend(ne);

	map.fitBounds(newBoundary);

	return this;
}