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ApsaraDB RDS:ST_UpperLeftX

Last Updated:Sep 22, 2023

This topic describes the ST_UpperLeftX function. This function queries the upper-left X coordinate of a raster object in the spatial reference system.

Prerequisites

The raster object has a spatial reference system identifier (SRID). You can run the following command to check whether the raster object has an SRID. If the raster object does not have an SRID, call the ST_SetSrid function to configure an SRID for the raster object.

SELECT ST_SRID(raster_obj) FROM raster_table;

Syntax

float8 ST_UpperLeftX(raster raster_obj)

Parameters

Parameter

Description

raster_obj

The raster that you want to query.

Examples

SELECT st_upperleftx(raster_obj), st_upperlefty(raster_obj)
FROM raster_table;

 st_upperleftx | st_upperlefty 
---------------+---------------
        440720 |       3751320