Point Constructors - Ocient Documentation

POINT constructors use geospatial data to create a POINT object.

ST_CENTROID

Returns a POINT that is the geographic center of mass of a specified geospatial object. The geographic center of mass is calculated by taking the average of all points on a three-dimensional sphere, projecting the resultant point onto the sphere, and converting it back to latitude and longitude coordinates. Syntax

SQL

ST_CENTROID( geo [, use_spheroid ] )

Argument	Data Type	Description
`geo`	`POINT`, `LINESTRING`, or `POLYGON`	A geospatial object that the function analyzes to compute its geometric center.
`use_spheroid`	`BOOLEAN`	Optional. If this argument is `TRUE`, the function computes the centroid using a spheroid model instead of a spherical model. If you do not specify this value, the value defaults to `FALSE`.

Example

SQL

SELECT ST_CENTROID(ST_POLYGON('POLYGON((1 1, 2 1, 2 2, 1 1))'));

Output: POINT(1.66 1.33)

ST_GEOGPOINT

Alias for ST_POLYGON(ST_LINESTRING(ARRAY(ST_POINT(lon, lat)))). Creates and returns a POLYGON geography with a single point, defined by the longitude and latitude specified for the function. Syntax

SQL

ST_GEOGPOINT(lon, lat)

Argument	Data Type	Description
`lon`	`DOUBLE`	A longitude coordinate to be used to create a `POLYGON` with a single point.
`lat`	`DOUBLE`	A latitude coordinate to be used to create a `POLYGON` with a single point.

Example

SQL

SELECT ST_GEOGPOINT(41.882548,-87.63922);

Output: POLYGON((41.882548 -87.63922))

ST_MAKEPOINT

Alias for ST_POINT.

ST_POINT

Creates a POINT from the specified input arguments.

ST_POINT(binary) [#st_point-binary]

Alias for ST_POINTFROMWKB. Creates a POINT from the specified BINARY value, which must represent a point in WKB format. Syntax

SQL

ST_POINT(binary)

Argument	Data Type	Description
`binary`	`BINARY`	A binary value in WKB format that represents a `POINT`.

Example

SQL

SELECT ST_POINT(BINARY('0x0101000000000000000000f03f0000000000000040'));

Output: POINT(1 2)

ST_POINT(char) [#st_point-char]

Creates a POINT from a CHAR value that represents a point in WKT format. Syntax

SQL

ST_POINT(char)

Argument	Data Type	Description
`char`	`CHAR`	A `CHAR` that represents a `POINT` in WKT format.

Example

SQL

SELECT ST_POINT('POINT(1 2)');

Output: POINT(1 2)

ST_POINT(lon, lat)

Creates a POINT defined with the values provided for the longitude and latitude coordinates. Syntax

SQL

ST_POINT(lon, lat)

Argument	Data Type	Description
`lon`	`DOUBLE`	A `DOUBLE` value that represents a longitude coordinate.
`lat`	`DOUBLE`	A `DOUBLE` value that represents a latitude coordinate.

Example

SQL

SELECT ST_POINT(87.6386, 41.8843);

Output: POINT(87.6386 41.8843)

ST_POINTFROMEWKT

Alias for ST_POINT. Creates a POINT using an EWKT-formatted CHAR as an input argument. Syntax

SQL

ST_POINTFROMEWKT(srid_char)

Argument	Data Type	Description
`srid_char`	`CHAR`	A string that includes a Spatial Reference Identifier (SRID) value and an EWKT-formatted value that represents a `POINT`. Separate the values in the string by a semicolon using this format: `'SRID = value; point_value'` The input string must include the `SRID = value;` component. However, the database ignores this component as all geography types are `SRID = 4326`.

Example

SQL

SELECT ST_POINTFROMEWKT('SRID=4326;POINT(1 2)');

Output: POINT(1 2)

ST_POINTFROMGEOJSON

Creates a POINT represented by the specified GeoJSON value as an input argument. A second optional BOOLEAN argument determines if the specified GeoJSON should be converted from a planar to a geodesic representation. If you specify a NULL value for either argument, the function returns NULL. Syntax

SQL

ST_POINTFROMGEOJSON(geojson [, geodesic ] )

Argument	Data Type	Description
`geo_json`	`STRING`	A string of a GeoJSON. Valid GeoJSON formats follow standards, which you can generate using the ST_ASGEOJSON function. If you specify an invalid GeoJSON, the behavior of the function is undefined. The function returns NULL if any argument is NULL.
`geodesic`	`BOOLEAN`	Optional. If you set this argument to `TRUE`, the specified GeoJSON is converted from a planar to a geodesic representation. This does not affect POINT geospatial objects. The default value is `FALSE`.

Examples In this example, the function captures a POINT from an empty GeoJSON representation.

SQL

SELECT ST_POINTFROMGEOJSON('{"type":"Point","coordinates":[]}',false);

Output: POINT EMPTY In this example, the function captures a POINT from a GeoJSON representation.

SQL

SELECT ST_POINTFROMGEOJSON('{"type":"Point","coordinates":[1,1]}',false);

Output: POINT(1 1)

ST_POINTFROMGEOHASH

Creates a POINT represented by the specified geohash. Syntax

SQL

ST_POINTFROMGEOHASH(geohash)

Argument	Data Type	Description
`geohash`	`STRING`	A string of a valid geohash. Valid geohashes contain only the characters `0123456789bcdefghjkmnpqrstuvwxyz`. If you specify an invalid geohash, the function throws an `INVALID_ARGUMENT` error. The function returns NULL if this argument is NULL.

Examples

SQL

SELECT ST_POINTFROMGEOHASH('c0w3hf1s70w3hf1s70w3');

Output: POINT(-126.00000000000003 48.00000000000007)

SQL

SELECT ST_POINTFROMGEOHASH('kzn21');

Output: POINT(42.60498046875 -5.60302734375)

ST_POINTFROMTEXT

Alias for ST_POINT(char).

ST_POINTFROMWKB

Alias for ST_POINT(binary). Geospatial Data Types Conversion Functions

​ST_CENTROID

​ST_GEOGPOINT

​ST_MAKEPOINT

​ST_POINT

​ST_POINT(binary) [#st_point-binary]

​ST_POINT(char) [#st_point-char]

​ST_POINT(lon, lat)

​ST_POINTFROMEWKT

​ST_POINTFROMGEOJSON

​ST_POINTFROMGEOHASH

​ST_POINTFROMTEXT

​ST_POINTFROMWKB

​Related Links

ST_CENTROID

ST_GEOGPOINT

ST_MAKEPOINT

ST_POINT

ST_POINT(binary) [#st_point-binary]

ST_POINT(char) [#st_point-char]

ST_POINT(lon, lat)

ST_POINTFROMEWKT

ST_POINTFROMGEOJSON

ST_POINTFROMGEOHASH

ST_POINTFROMTEXT

ST_POINTFROMWKB

Related Links