Geometry construction ​

Construct geometry values with CAST or write JSON coordinate arrays to a geometry column. The aliases define how coordinates nest and validate the resulting shape.

Shapes ​

A Point is a pair of Float64 coordinates. MultiPoint, Ring and LineString are arrays of Points. A Polygon is an array of Rings, a MultiLineString is an array of LineStrings, and a MultiPolygon is an array of Polygons.

The declarations validate field types and nesting, not topological correctness. They do not detect self-intersections or assign a coordinate reference system.

Examples ​

A point and independent points ​

SELECT CAST('[1,2]' AS Point),
       CAST('[[1,2],[3,4]]' AS MultiPoint)
FORMAT csv;

"[1,2]","[[1,2],[3,4]]"

A polygon boundary ​

SELECT CAST('[[[0,0],[2,0],[2,2],[0,2]]]' AS Polygon)
FORMAT csv;

"[[[0,0],[2,0],[2,2],[0,2]]]"

Use point_in_polygon to test containment. See geometry types for the alias table and GeoJSON for interchange.