Places

NIP-Places#

draft optional

This NIP defines an addressable event for a place: a physical point of interest such as a restaurant, hotel, museum, shop or park. A place event carries a name, precise coordinates, a searchable geohash index, categories and optional descriptive attributes.

A place event is the author's record of a place. It does not claim ownership of the place, and several authors MAY publish records of the same real-world place.

Place event#

A place is a kind:31300 addressable event. Its address is 31300:<pubkey>:<d>, so other events reference it with an a tag.

.content is an optional plain-text description of the place.

To edit a place, the author publishes a new event with the same d tag, which replaces the previous one. To remove a place, the author publishes a NIP-09 deletion request.

Tags#

Tag	Status	Description
d	required	Unique identifier for this place, chosen by the author. A random UUID is RECOMMENDED so the place can be renamed without changing its address.
name	required	Display name of the place.
geo	required	Coordinates, as an RFC 5870 geo-path, see Coordinates.
g	recommended	Geohashes derived from geo, see Geohash.
location	recommended	Human-readable location, see Location.
t	optional	Category or label, lowercase. MAY be repeated.
r	optional	Website of the place.
i	optional	NIP-73 external identifier linking the place to an external registry. MAY be repeated, each with its k tag.
osm:<key>	optional	OpenStreetMap attribute, see OpenStreetMap attributes.

All tag values are strings. Clients MUST ignore tags they do not understand.

Coordinates#

The geo tag is the authoritative position of the place, as geometric coordinates. Its value MUST be a geo-path as defined in RFC 5870, that is, a geo URI without its geo: scheme prefix. It gives latitude then longitude in decimal degrees, with . as the decimal separator. Positive values are north and east, negative values south and west. Coordinates MUST use the WGS84 datum, which is the RFC 5870 default: the value MUST NOT include a crs parameter other than wgs84.

["geo", "48.86004,2.32663"]

Geohash#

Events SHOULD include g tags as defined in NIP-52, holding lowercase geohashes of the geo position at lengths 4, 6 and 9. They MAY include other lengths.

A g tag is consistent with geo if the geo position lies within or on the boundary of the geohash cell. If a g tag is inconsistent with geo, clients MUST use geo and SHOULD ignore that g tag.

Location#

The location tag describes where the place is, as a single human-readable string. It is usually a postal address, but MAY be any description people use locally to find the place, such as a village, a landmark or a post office box where no street address exists. It SHOULD be written in the format customary where the place is. Events SHOULD include it when such a description is known, and SHOULD include at most one.

Clients SHOULD display location as-is and MUST NOT rely on parsing it. The place's position is always given by geo.

["location", "1 Rue de la Légion d'Honneur, 75007 Paris, France"],
["location", "Village de Sanankoroba near Kati, B.P. 88, Mali"]

OpenStreetMap attributes#

OpenStreetMap is the largest open dataset of places, with an established vocabulary of attributes. The osm: prefix lets events carry those attributes without redefining them, and keeps them from colliding with other nostr tags.

A tag whose name starts with osm: carries an OpenStreetMap attribute. The rest of the tag name, after the first :, is the OSM key. The value MUST follow the OSM conventions for that key. For example, osm:addr:street carries the OSM key addr:street.

Any OSM key MAY be used, and clients decide which ones to support. For illustration, common keys for places include:

Tag	Meaning
osm:amenity, osm:shop, osm:tourism, osm:leisure	OSM category, e.g. restaurant, bakery, museum, park
osm:opening_hours	Opening hours, in the OSM opening_hours syntax
osm:phone	Phone number, international format
osm:cuisine	Cuisine, OSM values, ;-separated
osm:wheelchair	yes, limited or no
osm:addr:*	Structured address

Clients that do not understand an osm: tag MAY display it as a generic key and value, or ignore it.

Related events#

This NIP relies on existing NIPs rather than defining new mechanisms:

• External identifiers. i tags follow NIP-73 and link a place to an entry in another registry. A place without any external identifier is fully valid; its identity is its Nostr address.
• Application labels. Clients MAY attach their own labels using NIP-32, with an L namespace and l tags, either on their own place events or in a kind:1985 label event referencing the place with an a tag.
• Collections. Users MAY group places into NIP-51 sets referencing places with a tags. Private entries MAY be encrypted as NIP-51 describes.
• Comments and reviews. Clients MAY use NIP-22 comments on place events.

Example#

{
  "kind": 31300,
  "pubkey": "<pubkey>",
  "created_at": 1727740800,
  "content": "Impressionist masterpieces in a former Beaux-Arts railway station.",
  "tags": [
    ["d", "a3f9c2e1-7b4d-4c8a-9e2f-1d6b8a0c5e7f"],
    ["name", "Musée d'Orsay"],
    ["geo", "48.86004,2.32663"],
    ["g", "u09t"],
    ["g", "u09tuy"],
    ["g", "u09tuywnq"],
    ["location", "1 Rue de la Légion d'Honneur, 75007 Paris, France"],
    ["t", "museum"],
    ["t", "art"],
    ["r", "https://www.musee-orsay.fr"],
    ["osm:tourism", "museum"],
    ["osm:opening_hours", "Tu-Su 09:30-18:00; Th 09:30-21:45"],
    ["osm:wheelchair", "yes"],
    ["osm:addr:housenumber", "1"],
    ["osm:addr:street", "Rue de la Légion d'Honneur"],
    ["osm:addr:postcode", "75007"],
    ["osm:addr:city", "Paris"],
    ["osm:addr:country", "FR"]
  ],
  "id": "<id>",
  "sig": "<sig>"
}