If you can determine your position, it's important to ensure that you know how to describe it. This is best illustrated with latitude and longitude, the most internationally recognised coordinate system used on all sea and air charts as well as most GPSes and mobile phones. Many instruments display position in different format and if you say it wrong, it's possible to send the rescuers to the other side of the planet, which isn't going to help. If you follow this rule of the numbers and symbols, it doesn't matter what format the device uses, you'll always be able to convey your correct position so that the search and rescue crew are tasked to the right location.
