Analytics Toolbox for BigQuery

Analytics Toolbox for BigQuery

Github Code

clustering

This module contains functions that perform clustering on geographies.

ST_CLUSTERKMEANS

Description

Takes a set of points and partition them into clusters using the k-mean. It uses the k-means algorithm. Returns an array of tuples with the cluster index for each of the input features and the input geometry.

  • geog: ARRAY<GEOGRAPHY> points to be clustered.
  • numberOfClusters: INT64|NULL numberOfClusters that will be generated. If NULL the default value Math.sqrt(<NUMBER OF POINTS>/2) is used.

Return type

ARRAY<STRUCT<cluster INT64, geom GEOGRAPHY>>

Example

1
2
3
4
5

SELECT `carto-un`.carto.ST_CLUSTERKMEANS([ST_GEOGPOINT(0, 0), ST_GEOGPOINT(0, 1), ST_GEOGPOINT(5, 0), ST_GEOGPOINT(1, 0)], 2);
-- {cluster: 1, geom: POINT(0 0)}
-- {cluster: 1, geom: POINT(0 1)}
-- {cluster: 0, geom: POINT(5 0)}
-- {cluster: 1, geom: POINT(1 0)}