if (!(position instanceof Point))
throw new IllegalArgumentException("The W3C Encoding only supports Points");
Element el = element.getExtension(QNAME_W3C_LAT);
if (el != null) el.discard();
el = element.getExtension(QNAME_W3C_LONG);
if (el != null) el.discard();
Point point = (Point) position;
ExtensibleElement p = element.addExtension(QNAME_W3C_POINT);
p.addSimpleExtension(QNAME_W3C_LAT, Double.toString(point.getCoordinate().getLatitude()));
p.addSimpleExtension(QNAME_W3C_LONG, Double.toString(point.getCoordinate().getLongitude()));