public static DecimalType CalculateDistance(DecimalType latitude1, DecimalType longitude1, DecimalType latitude2,
DecimalType longitude2)
{
if (latitude1.IsValid && longitude1.IsValid && latitude2.IsValid && longitude2.IsValid)
{
return
(new DecimalType(
CalculateDistance(DecimalType.ToDouble(latitude1), DecimalType.ToDouble(longitude1),
DecimalType.ToDouble(latitude2), DecimalType.ToDouble(longitude2))));
}
else
{
return(-1);
}
}