If the initial departure was from North Hemisphere and not from the South as it is on this question, we would have to add it to our initial latitude the latitude that we change (and not subtract as you did here, right)???
In order to decide whether to add or to subtract you need 2 information: 1. Where are you from? 2. In what direction are you moving to? How to use the information? Latitude If you are in Nothern Hemisphere (North Latitude) and your direction of travel is towards the north, you add the latitude change. If you are in the Northern Hemisphere (North Latitude) and your direction of travel is towards the South, you subtract the latitude change. Longitude If you are in the Eastern Hemisphere (East Longitude) and your direction of travel is towards the West, you subtract the longitude change. If you are in the Eastern Hemisphere (East Longitude) and your direction of travel is towards the East, you add the longitude change. Summary Use the following table as guidance Start Direction Operation NH North Add NH South Minus SH North Minus SH South Add EH East Add EH West Minus WH East Minus WH West Add NH - Nothern Hemisphere (North Latitude) SH - Southern Hemisphere (South Latitude) EH - Eastern Hemisphere (East Longitude) WH - Western Hemisphere (West Longitude) I hope this explanation helps you to understand the concept.
