Presented by Marc Tobias Metten of the OpenCage Geocoder team at FOSSGIS2015 in Münster, Germany on 11th March 2015

1. OpenCage FOSSGIS 2015
http://worldwideberlin.com/

2. OpenCage FOSSGIS 2015
Overview
I. place name disambiguation (homonyms)
– with & without spellcheck
II. Nominatim
III. other (open data) geocoders
– 2015 trends
– opportunities to share data, config, tests
IV. shared ranking/scoring data

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OpenCage Geocoder

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Welches Münster meinen sie?

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Nominatim geocoder

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Mühlheim vs Mülheim

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“eifelturm”

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“eiffel turm”

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“eiffeltower” => no result

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“eifel tower”
=> fair ground, Varna Bulgaria (fixed last week)

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“eiffel tower”
=> one in Paris
=> replicas around the world
=> restaurants around the world

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http://www.openstreetmap.org/#map=17/39.80885/116.28163

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Nominatim
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OSM data, minutely updates
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+ UK postal codes, TIGER
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1TB PostGIS
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import in C, setup scripts in PHP, Postgres stored
procedures, PHP frontend, Python&PHP test suite
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autocomplete if you add Photon geocoder
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no spellcheck

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regression/blackbox tests

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other geocoders
Closed source Open source, high resources Open source, low resources
Google Maps Mapzen “Pelias” OpenStreetMap “Nominatim”
Bing/Yahoo Mapbox “Carmen” OpenCage (multiple)
Mapquest Mapquest open (Nominatim) geonames
ESRI/ArcGIS Online Foursquare “Quattroshapes” geocod.io (Tiger data)
Baidu Scout Photon (Nominatim)
Yandex Cloudmade geo.io (Nominatim)
TomTom DSTK (Tiger, geonames)
Amazon (Android only) SmartyStreets
Telenav ...
Nokia/Ovi/Here
Apple (iOS only)
...

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trends
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SSD
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Add commercial sources
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Full builds, downloadable index
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High parallel (map/reduce, nodejs), cloud scaling,
noSQL
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Community building, guidelines
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Test suites

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typical features to improve
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horizontal scaling
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autocomplete
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spellcheck
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improve text parsing (App 3, 111-113b)
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crossings (Main & 2nd N, New Orleans)
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“4km north of $cityname on the N6”
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tests for non-latin alphabets
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postal code boundaries
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localsearch/POIs

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what should be shared
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aka. don't reinvent everything
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standard test suite to compare geocoders
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hierarchy data
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address parsing
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address formatting
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language configuration
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data parsing, e.g. OSM tags

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openaddresses.io
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110m addresses
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10GB of text files
1174 SMITH CREEK WAY, BRASSFIELD, WAKE FOREST, NC 27587
732 STEWARTS ROAD, LANEXA, VA 23124

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address formatting
https://github.com/lokku/address-formatting/
– configuration
– test cases for 33 countries
– reference implementation in Perl
{ country_code: 'dk', village: 'Ærøskøbing', county: 'Ærø
Municipality', house_number: '17A', neighbourhood: 'Paradiset',
postcode: '5970', road: 'Baggårde', state: 'Region of Southern Denmark'
}
Baggårde 17A, 5970 Ærøskøbing, Denmark
Adama Asnyka 1, 59-700 Bolesławiec, Poland
CAI, Cerrito 1250, Retiro, C1010AAZ Buenos Aires, Argentina

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wikipedia data

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core geocoding logic
1. tokenize
2. filter
•
fixed bounding box, browser window, country
•
OSM tags/POI search
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min-max admin
3. search
4. rank
•
country bias
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language bias (client, explicit)
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location boost (client, explicit, history)
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maybe: spellcheck
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maybe: retry/failover/remove phrases
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importance boost

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http://blog.mayflower.de/755-Schnelle-Volltextsuche-mit-Solr.html

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map to hierachy (ranks)
http://wiki.openstreetmap.org/wiki/Nominatim/Development_overview

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names, names, names

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name is one of many factors
ranking examples:
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Altona
– type: suburb vs train station vs town ins US/Canada
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Germany
– admin_level=2 (country) vs island
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Mt everest
– importance: viewpoint vs peak vs island
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Oktoberfest
– actually a alt_name of Theresienwiese
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Königsberg
– 10x a peak, 1x old_name of Kaliningrad
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Hitlerberg
– old_name:1934-1945 of Heigelkopf

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status on wikipedia_articles.bin
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version 1: wikipedia pageview logs
– https://en.wikipedia.org/wiki/Wikipedia:Notability
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version 2 (current): parsing wikipedia articles and count links
– last updated 2013
– 80m wikipedia entries + 15m redirects
– 0.6m places in OSM have wikipedia tag set (2013: 0.4m)
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Version 3 (TBD): parsing wikipedia geo exports
– http://de.wikipedia.org/wiki/Wikipedia:WikiProjekt_Georeferenzierung/Haupts
eite/Wikipedia-World/en
– 3.4m entries, more languages, regular dumps, new documentaton
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version 4 (?)
- used wikidata exports
- used by multiple geocoders

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what can mappers do?
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add wikipedia tags
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fix administrative levels
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don't add wrong names (typos)
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file bugs (github)
http://nominatim.openstreetmap.org/

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… and if all fails: rename city

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Questions ?
mtm@opencagedata.com