Queries the pixel values of the quantiles for a raster object.

Prerequisites

The quantiles of the raster object are calculated by using the ST_StatsQuantile function.

Syntax

raster ST_Quantile(raster raster_obj,
                   float8[] quantiles default NULL,
                   cstring bands default '',
                   boolean exclude_nodata_value default true, 
                   out integer band,
                   out float8 quantile,
                   out float8 value)

Parameters

Parameter Description
raster_obj The name of the raster object.
quantiles The quantiles whose pixel values you want to calculate. Valid values: 0.25, 0.5, and 0.75. You can specify one or more quantiles.
bands The serial numbers of the bands based on which the pixel values of the quantiles are calculated. Supported formats are '0-2' and '1,2,3'. Serial numbers start from 0. Default value: empty string (''). The default value specifies all bands.
exclude_nodata_value Specifies whether to include NoData values during calculation.
band Specifies to return the serial numbers of the bands.
quantile Specifies to return the quantiles.
value Specifies to return the pixel values.

Examples

-- Calculate the pixel value of the 0.25 quantile based on all bands.
SELECT  (ST_Quantile(rast, ARRAY[0.25], '0-2', true)). * FROM rat_quantile WHERE id = 1;
 band | quantile | value 
------+----------+-------
    0 |     0.25 |    11
    1 |     0.25 |    10
    2 |     0.25 |    50
(3 rows)

-- Calculate the pixel values of the 0.25, 0.5, and 0.75 quantiles based on band 0.
SELECT  (ST_Quantile(rast, NULL, '0', true)). * FROM rat_quantile WHERE id = 1;
 band | quantile | value 
------+----------+-------
    0 |     0.25 |    11
    0 |      0.5 |    11
    0 |     0.75 |    65
(3 rows)