data-services/geocoder/admin0

Admin0 Geocoder

Function

Accepts a list of terms. Terms are searched against the name_ column in admin0_synonyms. The name_ column is an automatically cleaned and populated column based on the raw values in name_ . The synonym table returns the proper ISO code (based on rank values in table below). The iso code is then matched against the single row in ne_admin0_v3 to return the polygon.

Creation steps

1. Upload fresh NaturalEarth data to ne_admin0_v3.
2. Delete all rows in the admin0_synonyms table.
3. If fresh, add all sql/indexes.sql and sql/triggers.sql
4. Upload the data/wikipedia_countries_native_names.csv table if it doesn't already exist
5. Run the sql/subdivide_polygons.sql
6. Run the sql/build_synonym_table.sql
7. If needed, load or replace the function with sql/geocoder.sql

Data Sources

(see the wiki page: Geocoder Data Sources #admin0-countries)

• natural earth data: ne_10m_admin_0_countries (version 3.0) which is currently stored in Geocoding.CartoDB as ne_admin0_v3

• native language spellings were gathered from http://en.wikipedia.org/wiki/List_of_countries_and_dependencies_and_their_capitals_in_native_languages and stored in data/wikipedia_countries_native_names.csv

Preparation details

Users dislike the NaturalEarth aggregation of French regions into the mainland France polygon. We have done a minimal amount of subdivision. This can be done by executing,

sql/subdivide_polygons.sql

Admin0_synonyms

Documentation for the creation of the geocoder synonym tables.

For use with the admin0_geocoder.

Ranks

rank number	origin data	origin column	description
0	natural earth 10m countries	name	literal name
1	natural earth 10m countries	name_alt	alternate name
2	wiki country navive names	country_endonym	local variation
3	natural earth 10m countries	adm0_a3	3 digit country code
4	natural earth 10m countries	abbrev	abbreviation
5	natural earth 10m countries	formal_en	formal english
6	natural earth 10m countries	brk_name	?
7	natural earth 10m countries	formal_fr	formal french

notes:

• The column adm0_a3 will be used as a unique identifier.
• The ranks are somewhat arbitrarily organized and should be modified later based on our users use of the geocoder (will users more commonly geocode an adm0_a3 or abbreviation?)
• I also forgot to assign a rank of 2 to a synonym.