ST_AsX3D-PolarDB(PolarDB)-阿里云帮助中心

Returns the Extensible 3D (X3D) XML representation of a geometry object as a text string.

Syntax

text ST_AsX3D(geometry g1, integer maxdecimaldigits, integer options)

Parameters

Parameter	Type	Description	Default
`g1`	geometry	The geometry object to convert.	—
`maxdecimaldigits`	integer	The maximum number of decimal places in the output coordinates.	15
`options`	integer	Specifies whether to represent coordinates with the X3D GeoCoordinates Geospatial node and whether to flip the x and y coordinates. See Options for details.	0

Options

Value	Behavior
`0`	Returns coordinates in database order (x, y). Default.
`1`	Flips x and y coordinates. When combined with the GeoCoordinates flag (`2`), applies `latitude_first` ordering.
`2`	Wraps coordinates in a GeoSpatial GeoCoordinates node. The geometry must use WGS 84 (SRID 4326); other SRIDs cause an error. This is the only GeoCoordinate type that is supported. Specify a spatial reference system based on the X3D specification. Output: `GeoCoordinate geoSystem='"GD" "WE" "longitude_first"'`.
`3`	Outputs `GeoCoordinate geoSystem='"GD" "WE" "latitude_first"'`.

Supported geometry types

ST_AsX3D supports circular strings, curves, polyhedral surfaces, triangles, triangulated irregular network (TIN) surfaces, and 3D objects.

Examples

Convert a polygon to X3D

SELECT ST_AsX3D(ST_GeomFromEWKT('POLYGON((1 1 0,1 2 0,2 2 0,2 1 0,1 1 0))'));

Output:

                           st_asx3d
---------------------------------------------------------------
 <IndexedFaceSet  convex='false' coordIndex='0 1 2 3'>
     <Coordinate point='1 1 0 1 2 0 2 2 0 2 1 0 ' />
 </IndexedFaceSet>
(1 row)