Microsyntax for location

[evanp]

"As an ActivityPub user, I want to include microsyntax in my posts to identify locations, so that I can experiment with geosocial features without server or client support."

[evanp]

One possibility is the machine tag format: https://www.flickr.com/groups/51035612836@N01/discuss/72157594497877875/

[evanp]

Another option is the "L:" prefix, which was defined by microsyntax.org (now offline)

[travisfw]

I want to put forth the option of Open Location Codes (OLC) aka Plus Codes as essentially geo hashtags. They have clear recognizable semantics (and even a regular expression, if you want "two problems").
Plenty of criticism for OLC is valid, but much of it applies to latlng as well.

I have my own wish list of features (top 2: not having odd shaped rectangles near the poles, and being able to easily talk about large regions) but when I went shopping for an extant system, OLC was the best I found.

[TallTed]

FWIW, at least some of microsyntax.org is on the wayback machine. I couldn't quickly find their definition of L:, but maybe someone familiar with the site can dig deeper.

[here]

Discussed on monthly geosocial call

• Consider adding osm unique ids as an option

[jeremiahlee]

My comments from the 2025-07-10 task force call:

Open Location Codes/Plus Codes are good for communicating lat/lon, but not the more broad concept of location.

Open Street Map ids capture the wide variety of location types (e.g. a business, a building, a street address, city, region) and are reasonably short.

I like the concept of a the microsyntax and Flickr machine tag format because it is straightforward to parse and offers extensibility to other id systems.

My proposal: L to indicate location, colon separator, OSM to indicate Open Street Map as the id data source, colon separator, OSM type, OSM id. Termination is indicated by end of line or space, as some location id systems use periods, hyphens, and other non-alphanumeric characters.

The OSM type+id follows Nominatim's query format.

Example: L:OSM:W621233451 for the Valdemarsviks rosarium

• https://nominatim.openstreetmap.org/ui/details.html?osmtype=W&osmid=621233451
• https://www.openstreetmap.org/way/621233451

An example of the extensibility: If someone preferred to use GERS, it could be formatted like: L:GERS:a0fc59f5-5f30-4b51-a69b-af3977557311 with GERS to indicate the id system and then its UUID at the end to do a look up

[evanp]

There are some other microsyntaxes for location!

• What Three Words convenient and memorable but proprietary
• Mapcode short and sweet
• Geohash long and precise

[evanp]

See also #26