private static void WriteArea(XmlWriter writer, NumericRepresentationValue area)
{
if (area == null || area.Value == null || area.Value.Value < 0)
writer.WriteAttributeString("D", "0");
else
{
var fieldArea = area.Value.ConvertToUnit(new CompositeUnitOfMeasure("m2"));
writer.WriteAttributeString("D", fieldArea.ToString(CultureInfo.InvariantCulture));
}
}