dataservices-api/API.md at 082d876c8df8da2eafcd7e9043201aba3069803e

Carla b93ed72037 Applies PR feedback and edits function names

2015-11-24 15:37:29 +01:00

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Geocoder API

Overview

The CartoDB Geocoder API allows you to match your data with geometries on your map. This geocoding service can be used programatically to geocode datasets via the CartoDB SQL API. It is fed from Open Data and it serves geometries for countries, provinces, states, cities, postal codes and IP addresses.

Quickstart

If you are using the set of APIs and libraries that CartoDB offers and you are handling your data with the SQL API, you can make your data visible in your maps by geocoding the dataset programatically.

Here's an example of how to geocode a single country:

https://{username}.cartodb.com/api/v2/sql?q=SELECT cdb_geocode_admin0_polygon('USA')&api_key={Your API key}

In order to geocode an existent CartoDB dataset, an SQL UPDATE statement must be used to populate the geometry column in the dataset with the results of the Geocoding API. If the column in which we are storing the country names for each one of our rows is called country_column, we can run the following statement in order to geocode the dataset:

https://{username}.cartodb.com/api/v2/sql?q=UPDATE {tablename} SET the_geom = cdb_geocode_admin0_polygon({country_column})&api_key={Your API key}

Notice that you can make use of Postgres or PostGIS functions in your Geocoder API requests, as the result of it will be a geometry that can be handled by the system. As an example, if you need to retrieve the centroid of a specific country, you can wrap the resulting geometry from the Geocoder API inside the PostGIS ST_Centroid function:

https://{username}.cartodb.com/api/v2/sql?q=SELECT ST_Centroid(cdb_geocode_admin0_polygon('USA'))&api_key={Your API key}

General concepts

The Geocoder API offers geocoding services on top of the CartoDB SQL API by means of a set of geocoding functions. Each one of these functions is oriented to one kind of geocoding operation and it will return the corresponding geometry (a polygon or a point) according to the input information.

The Geocoder API decouples the geocoding service from the CartoDB Editor, and allows to geocode data (being single rows, complete datasets or simple inputs) programatically through authenticated requests.

The geometries provided by this API are projected in the projection WGS 84 SRID 4326.

The Geocoder API can return different types of geometries (points or polygons) as result of different geocoding processes. The CartoDB platform does not support multigeometry layers or datasets, therefore the final users of this Geocoder API must check that they are using consistent geometry types inside a table to avoid further conflicts in the map visualization.

Authentication

All requests performed to the CartoDB Geocoder API must be authenticated with the user API Key. For more information about where to find your API Key and how to authenticate your SQL API requests, check the [SQL API authentication(http://docs.cartodb.com/cartodb-platform/sql-api/authentication/) guide.

Errors

Errors will be described in the response of the geocoder request. An example is as follows:

{
   error: [
        "function cdb_geocode_countries(text) does not exist"
   ]
}

Due to the fact that the Geocoder API is used on top of the CartoDB SQL API you can check the Making calls to the SQL API section to help you debug your SQL errors.

If the requested information is not in the CartoDB geocoding database, or if CartoDB is unable of recognizing your input and matching it with a result, the geocoding function will return null as a result.

Limits

The usage of the Geocoder API is subject to the CartoDB SQL API limits stated in our Terms of Service.

Reference

Geocoding functions

The available geocoding functions are listed below, grouped by categories.

Country geocoder

This function provides a country geocoding service. It recognizes the names of the different countries from different synonyms, such as their English name, their endonym, or their ISO2 or ISO3 codes.

cdb_geocode_admin0_polygon

cdb_geocode_admin0_polygon(country_name text)
- Parameters:
  - Name: country_name Type: text Description: Name of the country
- Return type: Geometry (polygon)
- Usage example:
  
  SELECT
```
SELECT cdb_geocode_admin0_polygon('France')
```
  UPDATE
```
UPDATE {tablename} SET {the_geom} = cdb_geocode_admin0_polygon({country_column})
```

Level-1 Administrative regions geocoder

The following functions provide a geocoding service for administrative regions of level 1 (or NUTS-1) such as states for the United States, regions in France or autonomous communities in Spain.

cdb_geocode_admin1_polygon

Functions:
- cdb_geocode_admin1_polygon(admin1_name text)
  - Parameters:
    - Name: admin1_name Type: text Description: Name of the province/state
  - Return type: Geometry (polygon)
  - Usage example:
    
    SELECT
```
SELECT cdb_geocode_admin1_polygon('Alicante')
```
    UPDATE
```
UPDATE {tablename} SET the_geom = cdb_geocode_admin1_polygon({province_column})
```
- cdb_geocode_admin1_polygon(admin1_name text, country_name text)
- Parameters:
  - Name: admin1_name Type: text Description: Name of the province/state
  - Name: country_name Type: text Description: Name of the country in which the province/state is located
- Return type: polygon
- Usage example:
SELECT SELECT cdb_geocode_admin1_polygon('Alicante', 'Spain')

UPDATE
```
UPDATE {tablename} SET the_geom = cdb_geocode_admin1_polygon({province_column}, {country_column})
```

City geocoder

The following functions provide a city geocoder service. It is recommended to use the more specific geocoding function -- the one that requires more parameters -- in order for the result to be as accurate as possible when several cities share their name.

cdb_geocode_namedplace_point

Functions:
- cdb_geocode_namedplace_point(city_name text)
- Parameters:
  - Name: city_name Type: text Description: Name of the city
- Return type: Geometry (point)
- Usage example:
  
  SELECT
```
SELECT cdb_geocode_namedplace_point('Barcelona')
```
  UPDATE
```
UPDATE {tablename} SET the_geom = cdb_geocode_namedplace_point({city_column})
```
- cdb_geocode_namedplace_point(city_name text, country_name text)
- Parameters:
  - Name: city_name Type: text Description: Name of the city
  - Name: country_name Type: text Description: Name of the country in which the city is located
- Return type: Geometry (point)
- Usage example:
  
  SELECT
```
SELECT cdb_geocode_namedplace_point('Barcelona', 'Spain')
```
  UPDATE
```
UPDATE {tablename} SET the_geom = cdb_geocode_namedplace_point({city_column}, 'Spain')
```
- cdb_geocode_namedplace_point(city_name text, admin1_name text, country_name text)
- Parameters:
  - Name: city_name Type: text Description: Name of the city
  - Name: admin1_name Type: text Description: Name of the province/state in which the city is located
  - Name: country_name Type: text Description: Name of the country in which the city is located
- Return type: Geometry (point)
- Usage example:
```
SELECT cdb_geocode_namedplace_point('New York', 'New York', 'USA')
```
  UPDATE
```
UPDATE {tablename} SET the_geom = cdb_geocode_namedplace_point({city_column}, {province_column}, 'Spain')
```

Postal codes geocoder

The following functions provide a postal code geocoding service that can be used to obtain points or polygon results. The postal code polygon geocoder covers the United States, France, Australia and Canada; a request for a different country will return an empty response.

cdb_geocode_postalcode_polygon

Functions:
- cdb_geocode_postalcode_polygon(postal_code text, country_name text)
  - Parameters:
    - Name: postal_code Type: text Description: Postal code
    - Name: country_name Type: text Description: Name of the country in which the postal code is located
  - Return type: Geometry (polygon)
  - Usage example:
```
SELECT cdb_geocode_postalcode_polygon('11211', 'USA')
```
    UPDATE
```
UPDATE {tablename} SET the_geom = cdb_geocode_postalcode_polygon({postal_code_column}, 'Spain')
```

** Note: For the USA, US Census ZCTAs are considered.

cdb_geocode_postalcode_point

Functions:
- cdb_geocode_postalcode_point(code text, country_name text)
  - Parameters:
    - Name: postal_code Type: text Description: Postal code
    - Name: country_name Type: text Description: Name of the country in which the postal code is located
  - Return type: Geometry (point)
  - Usage example:
```
SELECT cdb_geocode_postalcode_point('11211', 'USA')
```
    UPDATE
```
UPDATE {tablename} SET the_geom = cdb_geocode_postalcode_point({postal_code_column}, 'United States')
```

IP addresses Geocoder

This function provides an IP address geocoding service, for both IPv4 and IPv6 addresses.

cdb_geocode_ipaddress_point

Functions:
- cdb_geocode_ipaddress_point(ip_address text)
  - Parameters:
    - Name: ip_address Type: text Description: IPv4 or IPv6 address
  - Return type: Geometry (point)
  - Usage example:
```
SELECT cdb_geocode_ipaddress_point('102.23.34.1')
```
    UPDATE
```
UPDATE {tablename} SET the_geom = cdb_geocode_ipaddress_point('102.23.34.1')
```

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