fnGeographicalDistance
| lat1 : | Real (pass by const reference) |
| The latitude for the first coordinate. | |
| lon1 : | Real (pass by const reference) |
| The longitude for the first coordinate. | |
| lat2 : | Real (pass by const reference) |
| The latitude for the second coordinate. | |
| lon2 : | Real (pass by const reference) |
| The longitude for the second coordinate. |