Represent 3D geometries in tile coordinate system using ST_AsMVTGeom3D - PolarDB

Transforms a 3D geometry into the tile coordinate system required by ST_AsMVT3D.

Syntax

geometry ST_AsMVTGeom3D(
  geometry geom,
  box2d bounds,
  integer extent = 4096,
  integer buffer = 256,
  boolean clip_geom = true
);

Parameters

Parameter	Description
`geom`	The 3D geometry object to transform.
`bounds`	The rectangular boundaries of the tile, excluding the buffer. To generate boundaries, call ST_TileEnvelope.
`extent`	The tile size in the tile coordinate system. Valid values: 256 to 8192. Default value: 4096.
`buffer`	The buffer size in the tile coordinate system. Valid values: 1 to 4096. Default value: 256.
`clip_geom`	Specifies whether to clip the 3D geometry object at tile boundaries. Default value: true.

Usage notes

This function is upgraded from ST_AsMVTGeom with added support for transforming z-axis data of 3D geometries.
The bounds parameter must provide tile rectangle boundaries in the required spatial coordinate so that the geometry can be transformed and clipped correctly.
This function does not support 3D polygon objects that have inner shells.

Example

SELECT ST_AsText(ST_AsMVTGeom3D(ST_Transform('SRID=4326; LINESTRING(-10 -10 30, -10 -20 30)'::geometry, 3857), ST_TileEnvelope(1, 0, 0))) AS geom;

Output:

                                        geom
------------------------------------------------------------------------------------
 MULTILINESTRING Z ((3868.44444444444 4324.7197219642 30,3868.44444444444 4352 30))
(1 row)