public String ToPostValueString()
{
var sb = new StringBuilder();
if (_confidence.HasValue)
sb.Append("conf ").Append(_confidence.Value).Append("% ");
if (_resolution.HasValue)
sb.Append("res ").Append(_resolution.Value).Append("% ");
if (_errorLimits != null)
sb.Append("errlmt ").Append(_errorLimits);
if (_range != null)
sb.Append("range ").Append(_range);
return sb.ToString();
}