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Day1-1410-Challenges in geonames and address extraction

September 01, 2017

Day1-1410-Challenges in geonames and address extraction


September 01, 2017

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  1. Challenges in geonames
    and address extraction
    Prof. Stefan Keller

    Geometa Lab HSR

    University of Applied Sciences 

    Rapperswil (Switzerland)

    View Slide

  2. Agenda
    • Motivation

    • Geonames

    • Adresses

    • Issues

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  3. Geoname search:
    Where is Aizu-Wakamatsu?

    Address geocoding:
    Tokyo Central Post Office
    5-3, Yaesu 1-Chome
    Chuo-ku, Tokyo 100-8994

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  4. Search components
    • Data

    • Data pre-processing software

    • Search engine software

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  5. Geonames with
    containment hierarchy

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  6. Geoname Ex.: Aizu

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  7. Nominatim.osm.org

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  8. OSMNames.org

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  9. Enriched Geonames Data
    "name": "会津若松市",
    "alternative_names": „Aizuwakamatsu, Айдзувакамацу"
    "street": "",
    "county": "Fukushima",
    "city": "",
    "state": "Fukushima",
    "country": "Japan",
    "boundingbox": [139.8389,37.3229,140.1133,37.5831],
    "osm_id": "4174424",
    "type": "administrative",
    "importance": 0.4,

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  10. The power of hierarchy!
    1. country, national level (ev. main land!)

    2. state, subnational level

    3. city

    4. county/town

    5. village / suburb / neighborhood
    All administrative divisions are polygons (well: almost…)

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  11. What’s a name anyway?
    • Toponymie: Endonym, Exonym.Example

    • name = ձ௡एদ৓

    • name:jp = ձ௡एদ৓ (Aizu-Wakamatsu-jō)

    • name:en = Aizu-Wakamatsu Castle

    • name:de = Burg Aizu-Wakamatsu

    • alt_name:en = Tsuruga Castle

    • alt_name:jp = ௽ϲ৓ (Tsuru-ga-jō)

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  12. Issues in tagging geonames
    • Tag name: „Name is the name only“: Names are often misused to
    describe all kinds of things

    • Ranking of geonames!

    • Tag admin_level: There is no unified tagging yet in OSM for town
    parts and village parts

    • Issues in assigning hierarchy of city/town/village/suburb/

    • How to deal with objects of larger aerial extent? Currently often
    captured as node: which to choose? what is the extent? what is
    the bbox?

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  13. Addresses

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  14. (Postal Building) Addresses
    • Given list of street geonames as processed before,
    including hierarchy

    • Select all OSM objects (node, way, relation) with key
    „addr:housenumber“ (Karlsruhe Schema)

    • Goal: Generate list of addresses pointing to a street

    View Slide

  15. Karlsruhe Schema
    Addresses can be tagged with key addr:housenumber and
    other addr keys on…

    • an node, isolated or other (e.g. shops)

    • a node on top of a building boundary with tag entrance=yes

    • a node on a polygon with key building

    • a node on a polygon representing the perimeter of a site

    • an relation with key associatedStreet

    • an invisible line (way) with key addr:interpolation

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  16. Options to relate a house
    number to a street
    1. House number as part of relation exists? 

    2. Do addr:street or addr:place exists and match directly? 

    3. Apply fuzzy string/text search if street/place do not

    4. Apply street proximity search if there is no street/place

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  17. Not covered here
    • Ways with addr:interpolation tag

    • Nodes with associated_street tag

    • POIs without addr:* get addr:* from buildings with addr:s

    • Zip codes

    • …

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  18. Issues in tagging addresses
    • Misused name tags which introduce ambiguity

    • Sharing/deduplicating addr tags among objects inside a
    building polygon

    • addr nodes with entrance=yes sitting on top of a building
    (way): have to give addr to building (and building would
    have to give addy to everything inside

    • Special treatment of nodes with tag
    addr:housenumber=1;3;5 with values separated by

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  19. Message to go
    • Addresses are an important asset of OSM

    • Geonames too

    • Wishlist:

    • A more consistent assignment of admin levels is needed

    • More consistent name content

    • Discussion on how to map geonames of larger aerial extent

    • …

    View Slide