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Constructor functions

Use constructor functions to obtain binary representations of point, line, or polygon geometry data types. You can also use these functions to convert binary data to text, and obtain binary values for geometry data that is expressed as Well-Known Text (WKT).

ST_AsBinary(geometry)

Returns a varbinary data type that contains the WKB representation of the specified geometry. Example:

SELECT ST_AsBinary(ST_Point(-158.54, 61.56))

ST_AsText(geometry)

Converts each of the specified geometry data types to text. Returns a value in a varchar data type, which is a WKT representation of the geometry data type. Example:

SELECT ST_AsText(ST_Point(-158.54, 61.56))

ST_GeomAsLegacyBinary(geometry)

Returns a legacy varbinary from the specified geometry. Example:

SELECT ST_GeomAsLegacyBinary(ST_Point(-158.54, 61.56)

ST_GeometryFromText(varchar)

Converts text in WKT format into a geometry data type. Returns a value in a geometry data type. Example:

SELECT ST_GeometryFromText(ST_AsText(ST_Point(1, 2)))

ST_GeomFromBinary(varbinary)

Returns a geometry type object from a WKB representation. Example:

SELECT ST_GeomFromBinary(ST_AsBinary(ST_Point(-158.54, 61.56)))

ST_GeomFromLegacyBinary(varbinary)

Returns a geometry type object from a legacy varbinary type. Example:

SELECT ST_GeomFromLegacyBinary(ST_GeomAsLegacyBinary(ST_Point(-158.54, 61.56)))

ST_LineFromText(varchar)

Returns a value in the geometry data type line. Example:

SELECT ST_Line('linestring(1 1, 2 2, 3 3)')

ST_LineString(array(point))

Returns a LineString geometry type formed from an array of point geometry types. If there are fewer than two non-empty points in the specified array, an empty LineString is returned. Throws an exception if any element in the array is null, empty, or the same as the previous one. The returned geometry may not be simple. Depending on the input specfied, the returned geometry can self-intersect or contain duplicate vertexes. Example:

SELECT ST_LineString(ARRAY[ST_Point(-158.54, 61.56), ST_Point(-158.55, 61.56)])

ST_MultiPoint(array(point))

Returns a MultiPoint geometry object formed from the specified points. Returns null if the specified array is empty. Throws an exception if any element in the array is null or empty. The returned geometry may not be simple and can contain duplicate points if the specified array has duplicates. Example:

SELECT ST_MultiPoint(ARRAY[ST_Point(-158.54, 61.56), ST_Point(-158.55, 61.56)])

ST_Point(double, double)

Returns a geometry type point object. For the input data values to this function, use geometric values, such as values in the Universal Transverse Mercator (UTM) Cartesian coordinate system, or geographic map units (longitude and latitude) in decimal degrees. The longitude and latitude values use the World Geodetic System, also known as WGS 1984, or EPSG:4326. WGS 1984 is the coordinate system used by the Global Positioning System (GPS).

For example, in the following notation, the map coordinates are specified in longitude and latitude, and the value .072284, which is the buffer distance, is specified in angular units as decimal degrees:

SELECT ST_Buffer(ST_Point(-74.006801, 40.705220), .072284)

Syntax:

SELECT ST_Point(longitude, latitude) FROM earthquakes LIMIT 1

The following example uses specific longitude and latitude coordinates:

SELECT ST_Point(-158.54, 61.56)
FROM earthquakes
LIMIT 1

The next example uses specific longitude and latitude coordinates:

SELECT ST_Point(-74.006801, 40.705220)

The following example uses the ST_AsText function to obtain the geometry from WKT:

SELECT ST_AsText(ST_Point(-74.006801, 40.705220)) AS WKT

ST_Polygon(varchar)

Using the sequence of the ordinates provided clockwise, left to right, returns a geometry data type polygon. Starting in Athena engine version 2, only polygons are accepted as inputs. Example:

SELECT ST_Polygon('polygon ((1 1, 1 4, 4 4, 4 1))') 

to_geometry(sphericalGeography)

Returns a geometry object from the specified spherical geography object. Example:

SELECT to_geometry(to_spherical_geography(ST_Point(-158.54, 61.56)))

to_spherical_geography(geometry)

Returns a spherical geography object from the specified geometry. Use this function to convert a geometry object to a spherical geography object on the sphere of the Earth's radius. This function can be used only on POINT, MULTIPOINT, LINESTRING, MULTILINESTRING, POLYGON, and MULTIPOLYGON geometries defined in 2D space or a GEOMETRYCOLLECTION of such geometries. For each point of the specified geometry, the function verifies that point.x is within [-180.0, 180.0] and point.y is within [-90.0, 90.0]. The function uses these points as longitude and latitude degrees to construct the shape of the sphericalGeography result.

Example:

SELECT to_spherical_geography(ST_Point(-158.54, 61.56))