I don’t know if such an app exists, or if it is already part of the functionality of an existing app, however…

The basic premise is that the app gives you a notification when you hit a certain GPS location. This can be used by yourself or by others. If you want to send a notification to yourself, it uses no external app. If you want to send a notification to others, it uses Whatsapp.

Some of the uses could be:

• Once you arrive at location you need a notification (when I am near the local supermarket, “I need to go in and get potatoes”)
• Once another person arrives at a location they wll get a notification (“good luck with your job application interview!”)
• When you arrive back home (“hang up the washing”, “get the food out of the freezer”)
• When someone arrives at their holiday destination (“Have a great holiday, don’t forget to use sun tan lotion” – or something less patronising 🙂

The ‘internal’ (notifications to yourself) received notification screen should have a button for “Close/OK” and a button for “Next time” (so it will give you the message again the next time you hit the same GPS location).

The notification creation screen should have a zoomable, scrollable map on which you can drop a pin, specify an optional user from your contacts list (with name and phone number(s) listed, and if no user is specified, it will notify the person themselves), and type the actual notification message.

How to cause a message to pop up on another person’s screen depending on their GPS location? I don’t know, Although it would make the app less userfriendly and less instantly usable, it might actually require the recipient to also have the app installed (which will probably require some sort of registration system – if so then based on their international phone number?). Or maybe this could be limited only to the people you also have in “Find My” (which on iOS allows you to keep track of where people are). This latter option would greatly limit the app’s use, as you might want to send people notifications that you’re not so close with that they have allowed you to follow their whereabouts.

I don’t know if Whatsapp supports fully automated sending of messages, but I do know Whatsapp is usable by other apps so in the worst case it could automatically trigger Whatsapp with a predefined addressee and message, waiting for the user to actually confirm sending it manually.

Should anyone pick up his idea, I ask to be involved in the development and testing process. Thanks!