## Geocoder API

### Overview
### Quickstart
### General concepts
#### Auth?
#### Errors
#### Possible side-effects

For each function:
function names
function parameters and types 
return type for the functions  (Geometry or NULL if not found, with SRID 4326)
pre- and post-conditions or invariants

### Reference
#### Geocoding functions
##### Country geocoder functions
###### geocode_admin0_polygon
* Description:
 This function receives a country name and returns a polygon geometry (SRID 4326) for the corresponding input.
* Functions:
  * `geocode_admin0_polygon(country_name text)`
     * **Parameters**: A text parameter with the name of the country to geocode.
     * **Return type:** `polygon`
     * **Usage example:**
       `````
      SELECT geocode_admin0_polygon('France')
      `````

#### Level-1 Administrative regions geocoder
###### geocode_admin1_polygon
* Functions: 
  * `geocode_admin1_polygon(admin1_name text)`
    * **Parameters**: 
    * **Return type:** `polygon`
    * **Usage example:**
      `````
      SELECT geocode_admin1_polygon('Alicante')
      `````

  *  `geocode_admin1_polygon(admin1_name text, country_name text)`
    * **Parameters**: 
    * **Return type:** `polygon`
    * **Usage example:**
      `````
      SELECT geocode_admin1_polygon('Alicante', 'Spain')
      `````

#### City geocoder
##### geocode_namedplace_point
* Functions:
  *  `geocode_namedplace_point(city_name text)`
    * **Parameters**: 
    * **Return type:** `point`
    * **Usage example:**
      `````
      SELECT geocode_namedplace_point('Barcelona')
      `````

  *  `geocode_namedplace_point(city_name text, country_name text)`
    * **Parameters**: 
    * **Return type:** `point`
    * **Usage example:**
      `````
      SELECT geocode_namedplace_point('Barcelona', 'Spain')
      `````

  *  `geocode_namedplace_point(city_name text, admin1_name text, country_name text)`
    * **Parameters**: 
    * **Return type:** `point`
    * **Usage example:**
      `````
      SELECT geocode_namedplace_point('New York', 'New York', 'USA')
      `````

#### Postal codes geocoder
##### geocode_postalcode_polygon
* Functions:
  * `geocode_postalcode_polygon(code text, country_name text)`
    * **Parameters**: 
    * **Return type:** `polygon`
    * **Usage example:**
        `````
      SELECT geocode_postalcode_polygon('11211', 'USA')
      `````

##### geocode_postalcode_point
* Functions:
  * `geocode_postalcode_point(code text, country_name text)`
    * **Parameters**: 
    * **Return type:** `point`
    * **Usage example:**
        `````
      SELECT geocode_postalcode_point('11211', 'USA')
      `````

#### IP addresses Geocoder
##### geocode_ip_point(ipaddress text)
* Functions:
  * `geocode_ip_point(ipaddress text)`
    * **Parameters**: 
    * **Return type:** `point`
    * **Usage example:**
        `````
      SELECT geocode_ip_point('102.23.34.1')
      `````