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| README.md | ||
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
- Upload fresh NaturalEarth data to
ne_admin0_v3. The source file creates a table with the namene_10m_admin0_countries. - Delete all rows in the
admin0_synonymstable. - If fresh, add all
sql/indexes.sqlandsql/triggers.sql - Upload the
data/wikipedia_countries_native_names.csvtable if it doesn't already exist - Run the
sql/subdivide_polygons.sql - Run the
sql/build_synonym_table.sql - If needed, load or replace the function with
sql/geocoder.sql
Tables
admin0_synonyms
This table stores different synonyms per each country/region. It is populated through sql/build_synonym_table.sql.
Table stucture
Table "public.admin0_synonyms"
Column | Type | Modifiers | Storage | Stats target | Description
----------------------+--------------------------+----------------------------------------------------------------------+----------+--------------+-------------
name | text | | extended | |
rank | double precision | | plain | |
created_at | timestamp with time zone | not null default now() | plain | |
updated_at | timestamp with time zone | not null default now() | plain | |
the_geom | geometry(Geometry,4326) | | main | |
the_geom_webmercator | geometry(Geometry,3857) | | main | |
cartodb_id | integer | not null default nextval('admin0_synonyms_cartodb_id_seq'::regclass) | plain | |
adm0_a3 | text | | extended | |
name_ | text | | extended | |
Current indexes
Indexes:
"admin0_synonyms_pkey" PRIMARY KEY, btree (cartodb_id)
"admin0_synonyms_cartodb_id_key" UNIQUE CONSTRAINT, btree (cartodb_id)
"admin0_synonyms_the_geom_idx" gist (the_geom)
"admin0_synonyms_the_geom_webmercator_idx" gist (the_geom_webmercator)
"idx_admin0_synonyms_nam" btree (name)
"idx_admin0_synonyms_name" btree (lower(regexp_replace(name, '\W+'::text, ''::text)))
"idx_admin0_synonyms_name_" btree (name_)
"idx_admin0_synonyms_name_patt" btree (name_ text_pattern_ops)
"idx_admin0_synonyms_name_rank" btree (name_, rank)
"idx_admin0_synonyms_rank" btree (rank)
ne_admin0_v3
This table stores the geometries. It's obtained from Natural Earth Data and curated afterwards with sql/subdivide_polygons.sql.
Table structure
Table "public.ne_admin0_v3"
Column | Type | Modifiers | Storage | Stats target | Description
----------------------+--------------------------+----------------------------------------------------------------------------------+----------+--------------+-------------
the_geom | geometry(Geometry,4326) | | main | |
scalerank | integer | | plain | |
featurecla | text | | extended | |
labelrank | double precision | | plain | |
sovereignt | text | | extended | |
sov_a3 | text | | extended | |
adm0_dif | double precision | | plain | |
level | double precision | | plain | |
type | text | | extended | |
admin | text | | extended | |
adm0_a3 | text | | extended | |
geou_dif | double precision | | plain | |
geounit | text | | extended | |
gu_a3 | text | | extended | |
su_dif | double precision | | plain | |
subunit | text | | extended | |
su_a3 | text | | extended | |
brk_diff | double precision | | plain | |
name | text | | extended | |
name_long | text | | extended | |
brk_a3 | text | | extended | |
brk_name | text | | extended | |
brk_group | text | | extended | |
abbrev | text | | extended | |
postal | text | | extended | |
formal_en | text | | extended | |
formal_fr | text | | extended | |
note_adm0 | text | | extended | |
note_brk | text | | extended | |
name_sort | text | | extended | |
name_alt | text | | extended | |
mapcolor7 | double precision | | plain | |
mapcolor8 | double precision | | plain | |
mapcolor9 | double precision | | plain | |
mapcolor13 | double precision | | plain | |
pop_est | double precision | | plain | |
gdp_md_est | double precision | | plain | |
pop_year | double precision | | plain | |
lastcensus | double precision | | plain | |
gdp_year | double precision | | plain | |
economy | text | | extended | |
income_grp | text | | extended | |
wikipedia | double precision | | plain | |
fips_10_ | text | | extended | |
iso_a2 | text | | extended | |
iso_a3 | text | | extended | |
iso_n3 | text | | extended | |
un_a3 | text | | extended | |
wb_a2 | text | | extended | |
wb_a3 | text | | extended | |
woe_id | double precision | | plain | |
woe_id_eh | double precision | | plain | |
woe_note | text | | extended | |
adm0_a3_is | text | | extended | |
adm0_a3_us | text | | extended | |
adm0_a3_un | double precision | | plain | |
adm0_a3_wb | double precision | | plain | |
continent | text | | extended | |
region_un | text | | extended | |
subregion | text | | extended | |
region_wb | text | | extended | |
name_len | double precision | | plain | |
long_len | double precision | | plain | |
abbrev_len | double precision | | plain | |
tiny | double precision | | plain | |
homepart | double precision | | plain | |
cartodb_id | integer | not null default nextval('ne_10m_admin_0_countries_1_cartodb_id_seq1'::regclass) | plain | |
created_at | timestamp with time zone | not null default now() | plain | |
updated_at | timestamp with time zone | not null default now() | plain | |
the_geom_webmercator | geometry(Geometry,3857) | | main | |
Current indexes
Indexes:
"ne_10m_admin_0_countries_1_pkey1" PRIMARY KEY, btree (cartodb_id)
"idx_ne_admin0_v3_adm0_a3" UNIQUE, btree (adm0_a3)
"ne_10m_admin_0_countries_1_cartodb_id_key" UNIQUE CONSTRAINT, btree (cartodb_id)
"idx_ne_admin0_v3_a3" btree (adm0_a3)
"ne_10m_admin_0_countries_1_the_geom_webmercator_idx" gist (the_geom_webmercator)
"the_geom_4e1a2710_110a_11e4_b0ba_7054d21a95e5" gist (the_geom)
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. This is stored in data/ne_10m_admin_0_countries.zip
-
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
-
ISO 3166-2 codes were gathered from http://en.wikipedia.org/wiki/ISO_3166-2 and stored in data/wikipedia_iso_3166_2.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
In order to add new entries manually for admin0, table admin0_synonym_additions has been created.
The table contains the following columns to be populated:
-
adm0_a3 : ISO code for the region. Used to get the unique geometry for the region in terms of the synonym.
-
name: Actually, the synonym you want to include for a specific region (identified ad adm0_a3).
-
notes: Extra information as the source of the data. Use: 'data source: X'.
-
rank: Use '10' for manually curated additions.
The following query can be used:
INSERT INTO admin0_synonym_additions (adm0_a3, name, notes, rank) VALUES ($iso3_code, $synonym, $notes, 10)
Note: If you have a complete dataset of synonyms to be included, you will need to add it as part of the build script. If you need to add single entries for synonyms, they can be included in the admin0_synonym_additions table manually (or using the previously defined SQL query).
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 | wikipedia iso 3166 2 codes | iso_a2 | 2 digit country code |
| 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 |
| 8 | natural earth 10m countries | abbrev | abbreviation |
| 9 | natural earth 10m countries | subunit | complete literal name |
| 10 | admin0_synonym_additions | n/a | manually curated additions |
notes:
- The column
adm0_a3will 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
rankof2to a synonym.
Admin0 Synonym Service
If you need to look up the iso code for any list of countries without returning any geometries, you can use the endpoint defined in sql/synonym_service.sql. An example works like this,
SELECT (admin0_synonym_lookup(Array['United States', 'ESP'])).*
Testing
In order to test the data and the functions created under the script avaialble in this folder, you will need to run bash test.sh from test/data and test/functions. These functions test the amount of geometries generated, their bounding box, and the bounding box of the results generated by the geocoder functions. The tests also ensure a minimum quality in the synonyms table/function, checking that the official name (in English) for the regions is recognised.
Known issues
Historic
- [24/06/2015]:
- Added table structure and index information
- Adds known issues section
- [23/06/2015]:
- Change of SQL code in
subdivide_polygons.sqlin order to create all of them with ST_Collect, which makes uniform the geometry types: ST_MultiPolygon - Uploaded basic tests for administrative regions of level 0 geocoder
- Updated Testing section of
README.md
- Change of SQL code in
- [22/06/2015]:
- Removes code that provokes an empty geometry for
IOA, which was being stored as a null geometry. PR 144
- Removes code that provokes an empty geometry for