GridPoint GB vs SARLOC

If you have a paper Ordnance Survey (OS) map, GridPoint GB makes it easy to locate yourself — even when you've got no mobile reception. The app uses your iPhone's GPS and compass to provide your current grid reference and heading, and illustrates how to use this to locate yourself on the map. Coordinate conversions are implemented via OS's OSTN02, accurate to within 1m. The app also: * Includes an Apple Watch app and associated complication * Reports full numerical easting and northing, tetrad, raw latitude/longitude, a nearby postcode, and various heading parameters * Has a sharing facility so you can share, copy or store your location * Calculates next sunset and sunrise times * Can emit a distress signal, just in case All features are free to use — the in-app purchase is simply a tip you can give the developer to show appreciation. For details and instructions, please see http://mackerron.com/gridpointgb/ Please note: this app works ONLY in Britain (i.e. England, Scotland or Wales). It does not operate in other parts of the UK or British Isles and cannot provide coordinates in Northern Ireland or the Republic of Ireland, since a different coordinate system is used.

SARLOC was originally developed in 2009 by Russ Hore as a web application that allowed Search & Rescue (SAR) teams to locate you if you were unsure of your position. If you had a data signal, the SAR team could send you a message that allowed SARLOC to obtain your location and add it to the SAR teams mapping systems. Although it has been hugely successful, it does require a data signal to show you a location before it can be passed to the SAR teams. The SARLOC App will show you a location even if you do not have a data signal. If you are in voice communication with the SAR team you can tell them your location. If they provide you with a SARKey to enter into the App, you can share your location with them directly to their mapping systems. SARLOC is not a substitute for knowing how to navigate the outside world and it is essential that you learn proper navigation techniques before venturing into the wild. SARLOC requires you to be in contact with a SAR team before you can share your location with them. Starting SARLOC will not automatically notify anybody you require assistance.