ES|QL ST_UNION function

Returns the geometric union of two geometries, or unions all multi-values of a single geometry.

geomA

Expression of type geo_point, geo_shape, cartesian_point or cartesian_shape. If null, the function returns null.

geomB

Expression of type geo_point, geo_shape, cartesian_point or cartesian_shape. Must share the same coordinate reference system as the first parameter. If null, the function returns null. When omitted, all multi-values of geomA are unioned into a single geometry.

Returns the geometric union of two geometries. The result is a geometry that covers all points covered by either input geometry. Both geometries must share the same coordinate reference system.

Stack Planned The Elastic Stack includes Elastic's core products such as Elasticsearch, Kibana, Logstash, and Beats. Availability Planned We plan to add this functionality in a future Elastic Stack update. Subject to changes. Unless stated otherwise on the page, this functionality is available when your Elastic Stack is deployed on Elastic Cloud Hosted, Elastic Cloud Enterprise, Elastic Cloud on Kubernetes, and self-managed environments. This documentation corresponds to the latest patch available for each minor version. If you're not using the latest patch, check the release notes for changes. When called with a single multi-valued argument, all values at a position are unioned into one geometry.

ROW a = TO_GEOSHAPE("POLYGON ((0 0, 2 0, 2 2, 0 2, 0 0))"),
    b = TO_GEOSHAPE("POLYGON ((2 0, 4 0, 4 2, 2 2, 2 0))")
| EVAL unioned = ST_UNION(a, b)
| KEEP unioned

Union of two overlapping polygons

The union of two overlapping squares covers the area of both.