Key:is_in

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Public-images-osm logo.svg is_in
Osm element key.svg
Description
The is_in tag is used to index where a place or feature is.
Group: Boundary
Used on these elements
may be used on nodes
may be used on ways
may be used on areas
use on relations unspecified
Status: In use

When to use?

The is_in tag in OSM is one of the earliest tags in OSM, and is still in common use.

The is_in tag pre-dates boundary polygons. When a region has a well developed set of boundary polygons the information that could be placed in the is_in tag on an object can usually be derived from the boundaries that contain it. In this case, the information in the tag is redundant. Some contributors even go as far as to delete this tag when they see it as equivalent to the boundary information.

The tag still can contain important information when boundaries aren't fully developed. Even if the information is redundant, it permits simpler searching and easy disambiguation between two similarly named objects (without having to do extensive calculations to calculate all the containing boundaries).

Description

This tag lets you by specify, with words, where a place or feature is in the world. It can be used with anything, pubs, buildings, streets, parks but is most likely to be used with places. It is recommended that it is ALWAYS used with place tags to help some search engines - for example there are several places called San Francisco in the world (Philippines, Spain, USA), but to return only the one in California would required something like:

  • name=San Francisco
  • is_in=California; CA; USA

Although there is no requirement to write entities in a given order or to list everything, it is recommended that the reading order is from smaller to bigger entities and all full names are used up to the country level. Note these are valid, too, although not recommended:

  • name=SOMA
  • is_in=USA;CA;California;San Francisco
  • name=SOMA
  • is_in=San Francisco

For making categories

Less commonly, the tag can also be used to create a category for searching, e.g.

  • name=Canberra
  • is_in=capital_cities; Australian Capital Territory; ACT; Australia

means that Canberra can now appear in a list of capital cities of the world.

This can most likely be accomplished better with Proposed features/capital --Gorm 15:08, 6 April 2010 (UTC)
See also: Relations are not Categories

Improving accuracy

One weakness of the tag is that it might not be clear to processing programs exactly what each value stands for. In the above examples, is CA the short form for California or Canada? Is capital_cities a place or a category?

Relations is one solution, and also solves a redundancy issue, i.e. it is a waste writing is_in=Sweden,Stockholms län,Stockholm for every street in Stockholm.

Another solution is to use qualify is_in like this:

  • name=Canberra
  • place=city
  • is_in=capital_cities; Australian Capital Territory; ACT; Australia
  • is_in:state=Australian Capital Territory
  • is_in:state_code=ACT
  • is_in:country=Australia (use english name of the country)
  • is_in:country_code=AU (ISO 3166-1 two-letter country code, in UPPER CASE to conform with addr:country tag)

Any suburb, road or other feature in Canberra now needs just one tag to imply all the above:

Any of the place keys can be used as qualifiers:

See also

Tag "is_in"

  • Example Bedford
    place=town
    name=Bedford
    is_in=Bedfordshire; England; UK

Rationale

Basically, this means that programs can auto-generate indexes, of the form:

You are looking at data for Bedfordshire. Go up one level to England or Home Counties. Towns in Bedfordshire are: Ampthill, Bedford, Clapham, Dunstable...

  • more importantly when searching by street name, e.g. for 'High Street', it can tell you which of the many results you get back is likely to be the one you want, by saying 'High Street;Fulbourn;Cambridgeshire' and 'High Street;Chapel-en-le-Frith;Derbyshire'. David.earl October 14, 2006
This is already accomplished automatically without the use of is_in tag in Nominatim, the latest search engine. --Gorm 15:08, 6 April 2010 (UTC)
Yeah, Nominatim is great! Where can i download it for offline navigation on my android with 8 GB sdcard? --Themroc 20:46, 21 May 2011 (BST)

Extended

Note that the is_in tag useable for more than regions you can add geographic things like "The English Channel".

  • place=area
  • name=Isle of Wight
  • is_in=islands;english channel;osm_workshop_locations

Implementations