ST_CountAgg

Name

ST_CountAgg — Aggregate. Returns the number of pixels in a given band of a set of rasters. If no band is specified defaults to band 1. If exclude_nodata_value is set to true, will only count pixels that are not equal to the NODATA value.

Synopsis

bigint ST_CountAgg ( raster rast , integer nband , boolean exclude_nodata_value , double precision sample_percent ) ;

bigint ST_CountAgg ( raster rast , integer nband , boolean exclude_nodata_value ) ;

bigint ST_CountAgg ( raster rast , boolean exclude_nodata_value ) ;

Description

Returns the number of pixels in a given band of a set of rasters. If no band is specified nband defaults to 1.

If exclude_nodata_value is set to true, will only count pixels with value not equal to the NODATA value of the raster. Set exclude_nodata_value to false to get count all pixels

By default will sample all pixels. To get faster response, set sample_percent to value between zero (0) and one (1)

Availability: 2.2.0

Examples

WITH foo AS (
	SELECT
		rast.rast
	FROM (
		SELECT ST_SetValue(
			ST_SetValue(
				ST_SetValue(
					ST_AddBand(
						ST_MakeEmptyRaster(10, 10, 10, 10, 2, 2, 0, 0,0)
						, 1, '64BF', 0, 0
					)
					, 1, 1, 1, -10
				)
				, 1, 5, 4, 0
			)
			, 1, 5, 5, 3.14159
		) AS rast
	) AS rast
	FULL JOIN (
		SELECT generate_series(1, 10) AS id
	) AS id
		ON 1 = 1
)
SELECT
	ST_CountAgg(rast, 1, TRUE)
FROM foo;

 st_countagg
-------------
          20
(1 row)