Analytics Toolbox for Redshift

Analytics Toolbox for Redshift

lds

This module contains functions and procedures that make use of location data services, such as geocoding, reverse geocoding and isolines computation.

CREATE_ISOLINES

Description

Calculates the isolines (polygons) from given origins (points) in a table or query. It creates a new table with the columns of the input table or query except the geom_column plus the isolines in the column geom (if the input already contains a geom column, it will be overwritten). It calculates isolines sequentially in chunks of 100 rows.

  • input: VARCHAR(MAX) name of the input table or query.
  • output_table: VARCHAR(MAX) name of the output table. It will raise an error if the table already exists.
  • geom_column: VARCHAR(MAX) column name for the origin geometry column.
  • mode: VARCHAR(MAX) type of transport. Supported: ‘walk’, ‘car’.
  • range: INT range of the isoline in seconds (for range_type ‘time’) or meters (for range_type ‘distance’).
  • range_type: VARCHAR(MAX) type of range. Supported: ‘time’ (for isochrones), ‘distance’ (for isodistances).

Example

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CALL carto.CREATE_ISOLINES(
    'my-schema.my-table',
    'my-schema.my-output-table',
    'my_geom_column',
    'car', 60, 'time'
);
-- The table `my-schema.my-output-table` will be created
-- with the columns of the input table except `my_geom_column`.
-- Isolines will be added in the "geom" column.

GEOCODE

Description

Geocodes an address into a point with its geographic coordinates (latitude and longitude).

  • address: VARCHAR(MAX) input address to geocode.
  • country (optional): VARCHAR name of the country in ISO 3166-1 alpha-2. Defaults to ''.

Return type

GEOMETRY

Constraints

This function performs requests to the CARTO Location Data Services API. Redshift makes parallel requests depending on the number of records you are processing, potentially hitting the limit of the number of requests per seconds allowed for your account. The payload size of these requests depends on the number of records and could cause a timeout in the external function, with the error message External function timeout. The limit is around 500 records but could vary with the provider. To avoid this error, please try geocoding smaller volumes of data or using the procedure GEOCODE_TABLE instead. This procedure manages concurrency and payload size to avoid exceeding this limit.

Examples

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SELECT carto.GEOCODE('Madrid');
-- POINT(109.590465335923 34.1733770650093)
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SELECT carto.GEOCODE('Madrid', 'es');
-- POINT(51.405967078794 20.3365500266832)
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CREATE TABLE my_schema.my_geocoded_table AS
SELECT address, carto.GEOCODE(address) AS geom FROM my_table
-- Table my_geocoded_table successfully created.

GEOCODE_REVERSE

Description

Performs a reverse geocoding of the point received as input.

  • geom: GEOMETRY input point to obtain the address.
  • language (optional): VARCHAR(MAX) language in which results should be returned.

Return type

VARCHAR(MAX)

Constraints

This function performs requests to the CARTO Location Data Services API. Redshift makes parallel requests depending on the number of records you are processing, potentially hitting the limit of the number of requests per seconds allowed for your account. The payload size of these requests depends on the number of records and could cause a timeout in the external function, with the error message External function timeout. The limit is around 500 records but could vary with the provider. To avoid this error, please try processing smaller volumes of data.

Example

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SELECT carto.GEOCODE_REVERSE(ST_POINT(-74.0060, 40.7128));
-- 254 Broadway, New York, NY 10007, USA

GEOCODE_REVERSE_TABLE

Description

Reverse-geocodes an input table by adding a column address with the address coordinates a given point location column. It geocodes sequentially the table in chunks of 10 rows.

  • input_table: VARCHAR(MAX) name of the table to be reverse-geocoded. Please make sure you have enough permissions to alter this table, as this procedure will add two columns to it to store the geocoding result.
  • geom_column (optional): GEOMETRY column name for the geometry column that contains the points to be reverse-geocoded. Defaults to 'geom'.
  • address_column: VARCHAR(MAX) name of the column where the computed addresses will be stored. It defaults to 'address', and it is created on the input table if it doesn’t exist.
  • language (optional): VARCHAR(MAX) language in which results should be returned. Defaults to ''. The effect and interpretation of this parameter depends on the LDS provider assigned to your account.

If the input table already contains a column with the name address_column, only those rows with NULL values will be reverse-geocoded.

Examples

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CALL carto.GEOCODE_REVERSE_TABLE('my-schema.my-table');
-- The table `my-schema.my-table` with a column `geom` will be updated
-- adding the column `address`.
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CALL carto.GEOCODE_REVERSE_TABLE('my-schema.my-table', 'my_geom_column');
-- The table `my-schema.my-table` with a column `my_geom_column` will be updated
-- adding the column `address`.
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CALL carto.GEOCODE_REVERSE_TABLE('my-schema.my-table', 'my_geom_column', 'my_address_column');
-- The table `my-schema.my-table` with a column `my_geom_column` will be updated
-- adding the column `my_address_column`.
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CALL carto.GEOCODE_REVERSE_TABLE('my-schema.my-table', 'my_geom_column', 'my_address_column', 'en-US');
-- The table `my-schema.my-table` with a column `my_geom_column` will be updated
-- adding the column `my_address_column`.
-- The addresses will be in the (US) english language, if supported by the account LDS provider.

GEOCODE_TABLE

Description

Geocodes an input table by adding a column geom with the geographic coordinates (latitude and longitude) of a given address column. This procedure also adds a carto_geocode_metadata column with additional information of the geocoding result in JSON format. It geocodes sequentially the table in chunks of 100 rows.

  • input_table: VARCHAR(MAX) name of the table to be geocoded. Please make sure you have enough permissions to alter this table, as this procedure will add two columns to it to store the geocoding result.
  • address_column: VARCHAR(MAX) name of the column from the input table that contains the addresses to be geocoded.
  • geom_column (optional): VARCHAR(MAX) column name for the geometry column. Defaults to 'geom'.
  • country (optional): VARCHAR(MAX) name of the country in ISO 3166-1 alpha-2. Defaults to ''.

If the input table already contains a geometry column with the name geom_column, only those rows with NULL values will be geocoded.

Examples

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CALL carto.GEOCODE_TABLE('my-schema.my-table');
-- The table `my-schema.my-table` will be updated
-- adding the columns: geom, carto_geocode_metadata.
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CALL carto.GEOCODE_TABLE('my-schema.my-table', 'my_address_column');
-- The table `my-schema.my-table` will be updated
-- adding the columns: geom, carto_geocode_metadata.
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CALL carto.GEOCODE_TABLE('my-schema.my-table', 'my_address_column', 'my_geom_column');
-- The table `my-schema.my-table` will be updated
-- adding the columns: my_geom_column, carto_geocode_metadata.
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CALL carto.GEOCODE_TABLE('my-schema.my-table', 'my_address_column', 'my_geom_column', 'my_country');
-- The table `my-schema.my-table` will be updated
-- adding the columns: my_geom_column, carto_geocode_metadata.

ISOLINE

Description

Calculates the isoline polygon from a given point.

  • origin: GEOMETRY origin point of the isoline.
  • mode: VARCHAR(MAX) type of transport. Supported: ‘walk’, ‘car’.
  • range: INT range of the isoline in seconds (for range_type ‘time’) or meters (for range_type ‘distance’).
  • range_type: VARCHAR(MAX) type of range. Supported: ‘time’ (for isochrones), ‘distance’ (for isodistances).

Return type

GEOMETRY

Constraints

This function performs requests to the CARTO Location Data Services API. Redshift makes parallel requests depending on the number of records you are processing, potentially hitting the limit of the number of requests per seconds allowed for your account. The payload size of these requests depends on the number of records and could cause a timeout in the external function, with the error message External function timeout. The limit is around 500 records but could vary with the provider. To avoid this error, please try processing smaller volumes of data.

Examples

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SELECT carto.ISOLINE(ST_POINT(13.37749, 52.51578), 'car', 10, 'time');
-- POLYGON ((13.377142 52.516537, 13.377399 52.516193, 13.377743 52.51585, 13.377914 52.515335, 13.377743 52.51482, 13.377399 52.51482, 13.376713 52.515507, 13.376541 52.516022, 13.376627 52.516537, 13.376884 52.516708, 13.377142 52.516537))

LDS_QUOTA_INFO

Description

Returns statistics about the usage of Location Data Services for the user account, including the monthly and consumed quota for both geocoding and isolines services and their associated provider.

Return type

VARCHAR(MAX)

Example

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SELECT carto.LDS_QUOTA_INFO();
-- [{"monthly_quota":1000,"provider":"tomtom","service":"geocoding","used_quota":10},{"monthly_quota":100,"provider":"here","service":"isolines","used_quota":10}]