Name
ST_StdDev4ma — Raster processing function that calculates the standard deviation of pixel values in a neighborhood.
Synopsis
float8
ST_StdDev4ma
(
float8[][]
matrix
, text
nodatamode
, text[]
VARIADIC args
)
;
double precision
ST_StdDev4ma
(
double precision[][][]
value
, integer[][]
pos
, text[]
VARIADIC userargs
)
;
Description
Calculate the standard deviation of pixel values in a neighborhood of pixels.
![[Note]](./images/note.png)
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Variant 1 is a specialized callback function for use as a callback parameter to ST_MapAlgebraFctNgb . |
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Variant 2 is a specialized callback function for use as a callback parameter to ST_MapAlgebra (callback function version) . |
![[Warning]](./images/warning.png)
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Use of Variant 1 is discouraged since ST_MapAlgebraFctNgb has been deprecated as of 2.1.0. |
Availability: 2.0.0
Enhanced: 2.1.0 Addition of Variant 2
Examples
SELECT
rid,
st_value(
st_mapalgebrafctngb(rast, 1, '32BF', 1, 1, 'st_stddev4ma(float[][],text,text[])'::regprocedure, 'ignore', NULL), 2, 2
)
FROM dummy_rast
WHERE rid = 2;
rid | st_value
-----+------------------
2 | 1.30170822143555
(1 row)