> 1. A POI/favorites app that maintains a local database with an API for other apps to access it. Apps could then store markers there instead of in their own private db, so that points added on one map app can be instantly available in other apps.

Would an AT Protocol app or extension meet this need and requirements? By being stored in a PDS, the data can be permissioned, owned by the user, and easily migrated and/or shared.

https://atproto.com/blog/atproto-spaces-alpha

ATProto spaces: A new extension to ATProto that enables non-public data - https://news.ycombinator.com/item?id=49379732 - August 2026

▲ diggernet 3 days ago | parent | next [-]

No, it should be local-first. Private and offline by default. There could certainly be sync integrations using AT, Dropbox, iCloud, etc. Those could even be separate apps, using the same API to access the data. But that sort of thing should be secondary and optional.

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holgerschurig a day ago | parent | next [-]

OsmAnd already can store an unlimited amount of POIs locally. With text, icon, color, coordinates of corse.

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toomuchtodo 3 days ago | parent | prev [-]

Do you have any thoughts on data structure for local storage?

	▲	ihatehn 3 days ago \| parent \| next [-]
		We already do local bookmark backup, and use KML natively I think. It just doesn't sync, resolving sync conflicts is hard.
	▲	diggernet 3 days ago \| parent \| prev [-]
		Not really. I imagine a sqlite db, but I haven't thought about any particular schema.

▲ mariusor 3 days ago | parent | prev [-]

As technologists I think we should all be wary of "when all you have is a hammer" fallacy a little bit more.

▲ toomuchtodo 3 days ago | parent [-]

I certainly support local first, but if it is trivial to enable sharing of map favorites and POIs on open social rails, your risk is limited to "personal to you" locations being shared. JSON or Sqlite is fine for local storage of course. It is after all most likely simply a list of POI UUIDs/GUIDs identifiers and/or latitude/longitude coordinates with attribute fields. Foursquare and other social geo checkins long predate this, but I would agree good opsec should be the default, while still enabling open sharing with your data prevented from being captured and held hostage by Big Tech, imho.

I have many custom Google Maps lists I would love to share publicly on AT Protocol (mostly from collecting places in locations I've traveled to others would want to visit), for example, but would want some labels of places to remain private (homes of friends).

Export Google Maps List to CSV, KML and GPX - https://www.takeout-tools.com/blog/export-google-maps-list-c...

How to Turn Any List Into Google My Maps - https://www.lekoarts.de/how-to-turn-any-list-into-google-my-...

Google Maps Create a list of places - https://support.google.com/maps/answer/7280933

Example list:

   Title,Address,Notes,Latitude,Longitude
   "Golden Gate Bridge","San Francisco, CA","",37.8199,-122.4783
   "Fisherman's Wharf","San Francisco, CA","Best chowder",37.8080,-122.4177

	▲	diggernet 3 days ago \| parent [-]
		Yeah, there are all kinds of interesting things that can be done with shared data like this. But the first step is to have some standard ContentProvider to let apps share the data locally on a single device, similar to how other user data is handled. Because I'm tired of having several map apps installed for various reasons that all have separate favorites. Once that is in place, people can create apps that build on it in lots of different ways.