ST_CircularString(ST_Point,ST_Point,ST

ST_CircularString(ST_Point,ST_Point,ST_Point,...) constructor

Constructs a circular string value from a list of points in a specified spatial reference system.

Syntax

NEW ST_CircularString(pt1,pt2,pt3,[pt4,...,ptN])

Parameters

Name	Type	Description
pt1	ST_Point	The first point of an arc.
pt2	ST_Point	Any point on the arc between the first and last point.
pt3	ST_Point	The last point of an arc.
pt4,...,ptN	ST_Point	Additional points defining further arcs, each starting with the previous end point, passing through the first additional point and ending with the second additional point.

Constructs a circular string value from a list of points. At least three points must be provided. The first of these three is the start of an arc, the third point is the end of the arc, and the second point is any point on the arc between the first and third point. Additional points can be specified in pairs to add more arcs to the circular string. All of the specified points must have the same SRID. The circular string is constructed with this common SRID. All of the supplied points must be non-empty and have the same answer for Is3D and IsMeasured. The circular string is 3D if all of the points are 3D, and the circular string is measured if all of the points are measured.

Note

By default, ST_CircularString uses the original format for a geometry, if it is available. Otherwise, the internal format is used. For more information about internal and original formats, see STORAGE FORMAT clause, CREATE SPATIAL REFERENCE SYSTEM statement.

Standards and compatibility

Example

The following returns an error: at least three points must be specified.

SELECT NEW ST_CircularString( NEW ST_Point( 0, 0 ), NEW ST_Point( 1, 1 ) )

The following example returns the result CircularString (0 0, 1 1, 2 0).

SELECT NEW ST_CircularString( NEW ST_Point( 0, 0 ), NEW ST_Point( 1, 1 ), NEW ST_Point(2,0) )

The following returns an error: the first circular arc takes three points, and subsequent arcs take two points.

SELECT NEW ST_CircularString( NEW ST_Point( 0, 0 ), NEW ST_Point( 1, 1 ), NEW ST_Point(2,0), NEW ST_Point(1,-1) )

The following example returns the result CircularString (0 0, 1 1, 2 0, 1 -1, 0 0).

SELECT NEW ST_CircularString( NEW ST_Point( 0, 0 ), NEW ST_Point( 1, 1 ), NEW ST_Point(2,0), NEW ST_Point(1,-1), NEW ST_Point( 0, 0 ) )