ST_Envelope function to obtain the bounding box of a raster - PolarDB

Returns the bounding box of a raster as a geometry polygon.

Syntax

geometry ST_Envelope(raster source)
geometry ST_Envelope(raster source, integer pyramid)

Parameter	Description
`source`	The source raster.
`pyramid`	The pyramid level of the raster. Valid values start from 0. Default value: 0.

ST_Envelope returns the bounding box of a raster as a polygon.

Use the pyramid parameter to get the bounding box at a specific pyramid level.

Return the bounding box of a raster at the default pyramid level (0):

SELECT ST_AsText(ST_Envelope(rast_object))
FROM raster_table;

Result:

POLYGON((-180 90,180 90,180 -90,-180 -90,-180 90))

Return the bounding box at pyramid level 1:

SELECT ST_AsText(ST_Envelope(rast_object, 1))
FROM raster_table;

Result:

POLYGON((-180 90,180 90,180 -90,-180 -90,-180 90))