ST_MapAlgebra(回调函数版本)

ST_MapAlgebra(回调函数版本)
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Name

ST_MapAlgebra(回调函数版本) — 回调函数版本-返回给定一个或多个输入栅格、波段索引和一个用户指定的回调函数的单波段栅格。

Synopsis

raster ST_MapAlgebra ( rastbandarg[] rastbandargset , regprocedure callbackfunc , text pixeltype=NULL , text extenttype=INTERSECTION , raster customextent=NULL , integer distancex=0 , integer distancey=0 , text[] VARIADIC userargs=NULL ) ;

raster ST_MapAlgebra ( raster rast , integer[] nband , regprocedure callbackfunc , text pixeltype=NULL , text extenttype=FIRST , raster customextent=NULL , integer distancex=0 , integer distancey=0 , text[] VARIADIC userargs=NULL ) ;

raster ST_MapAlgebra ( raster rast , integer nband , regprocedure callbackfunc , text pixeltype=NULL , text extenttype=FIRST , raster customextent=NULL , integer distancex=0 , integer distancey=0 , text[] VARIADIC userargs=NULL ) ;

raster ST_MapAlgebra ( raster rast1 , integer nband1 , raster rast2 , integer nband2 , regprocedure callbackfunc , text pixeltype=NULL , text extenttype=INTERSECTION , raster customextent=NULL , integer distancex=0 , integer distancey=0 , text[] VARIADIC userargs=NULL ) ;

raster ST_MapAlgebra ( raster rast , integer nband , regprocedure callbackfunc , float8[] mask , boolean weighted , text pixeltype=NULL , text extenttype=INTERSECTION , raster customextent=NULL , text[] VARIADIC userargs=NULL ) ;

描述

返回给定一个或多个输入栅格、波段索引和一个用户指定的回调函数的单波段栅格。

RAST、RAST1、RAST2、RASTBAND边界集

对地图代数过程进行评估的栅格。

rastbandargset 允许对多个栅格和/或多个波段使用地图代数运算。请参见示例变体1。

Nband、nband 1、nband 2

要评估的栅格的波段编号。Nband可以是表示波段的整数或整数[]。对于2个栅格/2个波段的情况，nband 1是rast1上的波段，nband 2是rast2上的波段。

回调函数

The callbackfunc parameter must be the name and signature of an SQL or PL/pgSQL function, cast to a regprocedure. An example PL/pgSQL function example is:


CREATE OR REPLACE FUNCTION sample_callbackfunc(value double precision[][][], position integer[][], VARIADIC userargs text[])
    RETURNS double precision
    AS $$
    BEGIN
        RETURN 0;
    END;
    $$ LANGUAGE 'plpgsql' IMMUTABLE;

The callbackfunc must have three arguments: a 3-dimension double precision array, a 2-dimension integer array and a variadic 1-dimension text array. The first argument value is the set of values (as double precision) from all input rasters. The three dimensions (where indexes are 1-based) are: raster #, row y, column x. The second argument position is the set of pixel positions from the output raster and input rasters. The outer dimension (where indexes are 0-based) is the raster #. The position at outer dimension index 0 is the output raster's pixel position. For each outer dimension, there are two elements in the inner dimension for X and Y. The third argument userargs is for passing through any user-specified arguments.

Passing a regprocedure argument to a SQL function requires the full function signature to be passed, then cast to a regprocedure type. To pass the above example PL/pgSQL function as an argument, the SQL for the argument is:


'sample_callbackfunc(double precision[], integer[], text[])'::regprocedure

Note that the argument contains the name of the function, the types of the function arguments, quotes around the name and argument types, and a cast to a regprocedure .

遮罩

数字的n维数组(矩阵)，用于筛选传递给映射代数回调函数的单元格。0表示邻居小区值应被视为无数据，1表示值应被视为数据。如果权重设置为True，则这些值将用作乘数，以乘以邻近位置中该值的像素值。

加权

布尔值(TRUE/FALSE)，表示遮罩值是否应该加权(乘以原始值)(仅适用于接受遮罩的原件)。

像素类型

如果 pixeltype 传入后，新栅格的一个波段将属于该像素类型。如果将Pixeltype传递为空或忽略，则新的栅格标注栏将具有与第一个栅格的指定标注栏(对于范围类型：交集、并集、第一个、自定义)或相应栅格的指定标注栏(对于范围类型：第二个、最后一个)相同的像素类型。如果有疑问，请始终指定 pixeltype 。

输出栅格的结果像素类型必须是中列出的像素类型 ST_BandPixelType 或被省略或设置为空。

区段类型

可能的值包括交集(默认)、并集、第一个(一个栅格变体的默认)、第二个、最后一个、自定义。

自定义范围

如果 extentype 是自定义的，则必须提供栅格 customextent 。见备选案文1的示例4。

远距离消费

X方向上与参考单元格的距离(以像素为单位)。因此，生成的矩阵的宽度为 2*distancex + 1 。如果未指定，则仅考虑参考单元格(0的邻域)。

距离

Y方向上与参考单元格之间的距离，以像素为单位。生成的矩阵的高度将为 2*distancey + 1 。如果未指定，则仅考虑参考单元格(0的邻域)。

用户参数

的第三个参数 callbackfunc 是一种多变文本数组。所有尾随文本参数都传递给指定的 callbackfunc ，并包含在 userargs 论点。


	有关VARIADIC关键字的详细信息，请参阅的PostgreSQL文档和的“参数数目可变的SQL函数”一节查询语言(SQL)函数。


	这个文本[] 参数设置为 `callbackfunc` 是必需的，无论您是否选择将任何参数传递给回调函数进行处理。

变体1接受一个数组 rastbandarg 从而允许在许多栅格和/或许多波段上使用地图代数运算。请参见示例变体1。

变体2和3作用于一个栅格的一个或多个波段。请参见示例变体2和3。

变体4对两个栅格进行操作，每个栅格一个波段。请参见示例变体4。

可用性：2.2.0：能够添加面具

可用性：2.1.0

示例：变体1

一个栅格，一个波段

WITH foo AS (
    SELECT 1 AS rid, ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, 0, 1, -1, 0, 0, 0), 1, '16BUI', 1, 0) AS rast
)
SELECT
    ST_MapAlgebra(
        ARRAY[ROW(rast, 1)]::rastbandarg[],
        'sample_callbackfunc(double precision[], int[], text[])'::regprocedure
    ) AS rast
FROM foo

一个栅格，多个波段

WITH foo AS (
    SELECT 1 AS rid, ST_AddBand(ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, 0, 1, -1, 0, 0, 0), 1, '16BUI', 1, 0), 2, '8BUI', 10, 0), 3, '32BUI', 100, 0) AS rast
)
SELECT
    ST_MapAlgebra(
        ARRAY[ROW(rast, 3), ROW(rast, 1), ROW(rast, 3), ROW(rast, 2)]::rastbandarg[],
        'sample_callbackfunc(double precision[], int[], text[])'::regprocedure
    ) AS rast
FROM foo

几个栅格、几个波段

WITH foo AS (
    SELECT 1 AS rid, ST_AddBand(ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, 0, 1, -1, 0, 0, 0), 1, '16BUI', 1, 0), 2, '8BUI', 10, 0), 3, '32BUI', 100, 0) AS rast UNION ALL
    SELECT 2 AS rid, ST_AddBand(ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, 1, 1, -1, 0, 0, 0), 1, '16BUI', 2, 0), 2, '8BUI', 20, 0), 3, '32BUI', 300, 0) AS rast
)
SELECT
    ST_MapAlgebra(
        ARRAY[ROW(t1.rast, 3), ROW(t2.rast, 1), ROW(t2.rast, 3), ROW(t1.rast, 2)]::rastbandarg[],
        'sample_callbackfunc(double precision[], int[], text[])'::regprocedure
    ) AS rast
FROM foo t1
CROSS JOIN foo t2
WHERE t1.rid = 1
    AND t2.rid = 2

带有邻域的Coverage瓷砖的完整示例。此查询仅适用于PostgreSQL 9.1或更高版本。

WITH foo AS (
    SELECT 0 AS rid, ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, 0, 1, -1, 0, 0, 0), 1, '16BUI', 1, 0) AS rast UNION ALL
    SELECT 1, ST_AddBand(ST_MakeEmptyRaster(2, 2, 2, 0, 1, -1, 0, 0, 0), 1, '16BUI', 2, 0) AS rast UNION ALL
    SELECT 2, ST_AddBand(ST_MakeEmptyRaster(2, 2, 4, 0, 1, -1, 0, 0, 0), 1, '16BUI', 3, 0) AS rast UNION ALL

    SELECT 3, ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, -2, 1, -1, 0, 0, 0), 1, '16BUI', 10, 0) AS rast UNION ALL
    SELECT 4, ST_AddBand(ST_MakeEmptyRaster(2, 2, 2, -2, 1, -1, 0, 0, 0), 1, '16BUI', 20, 0) AS rast UNION ALL
    SELECT 5, ST_AddBand(ST_MakeEmptyRaster(2, 2, 4, -2, 1, -1, 0, 0, 0), 1, '16BUI', 30, 0) AS rast UNION ALL

    SELECT 6, ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, -4, 1, -1, 0, 0, 0), 1, '16BUI', 100, 0) AS rast UNION ALL
    SELECT 7, ST_AddBand(ST_MakeEmptyRaster(2, 2, 2, -4, 1, -1, 0, 0, 0), 1, '16BUI', 200, 0) AS rast UNION ALL
    SELECT 8, ST_AddBand(ST_MakeEmptyRaster(2, 2, 4, -4, 1, -1, 0, 0, 0), 1, '16BUI', 300, 0) AS rast
)
SELECT
    t1.rid,
    ST_MapAlgebra(
        ARRAY[ROW(ST_Union(t2.rast), 1)]::rastbandarg[],
        'sample_callbackfunc(double precision[], int[], text[])'::regprocedure,
        '32BUI',
        'CUSTOM', t1.rast,
        1, 1
    ) AS rast
FROM foo t1
CROSS JOIN foo t2
WHERE t1.rid = 4
    AND t2.rid BETWEEN 0 AND 8
    AND ST_Intersects(t1.rast, t2.rast)
GROUP BY t1.rid, t1.rast

与前面的例子类似，用于包含邻域的Coverage的瓷砖，但适用于PostgreSQL 9.0。

WITH src AS (
    SELECT 0 AS rid, ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, 0, 1, -1, 0, 0, 0), 1, '16BUI', 1, 0) AS rast UNION ALL
    SELECT 1, ST_AddBand(ST_MakeEmptyRaster(2, 2, 2, 0, 1, -1, 0, 0, 0), 1, '16BUI', 2, 0) AS rast UNION ALL
    SELECT 2, ST_AddBand(ST_MakeEmptyRaster(2, 2, 4, 0, 1, -1, 0, 0, 0), 1, '16BUI', 3, 0) AS rast UNION ALL

    SELECT 3, ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, -2, 1, -1, 0, 0, 0), 1, '16BUI', 10, 0) AS rast UNION ALL
    SELECT 4, ST_AddBand(ST_MakeEmptyRaster(2, 2, 2, -2, 1, -1, 0, 0, 0), 1, '16BUI', 20, 0) AS rast UNION ALL
    SELECT 5, ST_AddBand(ST_MakeEmptyRaster(2, 2, 4, -2, 1, -1, 0, 0, 0), 1, '16BUI', 30, 0) AS rast UNION ALL

    SELECT 6, ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, -4, 1, -1, 0, 0, 0), 1, '16BUI', 100, 0) AS rast UNION ALL
    SELECT 7, ST_AddBand(ST_MakeEmptyRaster(2, 2, 2, -4, 1, -1, 0, 0, 0), 1, '16BUI', 200, 0) AS rast UNION ALL
    SELECT 8, ST_AddBand(ST_MakeEmptyRaster(2, 2, 4, -4, 1, -1, 0, 0, 0), 1, '16BUI', 300, 0) AS rast
)
WITH foo AS (
    SELECT
        t1.rid,
        ST_Union(t2.rast) AS rast
    FROM src t1
    JOIN src t2
        ON ST_Intersects(t1.rast, t2.rast)
        AND t2.rid BETWEEN 0 AND 8
    WHERE t1.rid = 4
    GROUP BY t1.rid
), bar AS (
    SELECT
        t1.rid,
        ST_MapAlgebra(
            ARRAY[ROW(t2.rast, 1)]::rastbandarg[],
            'raster_nmapalgebra_test(double precision[], int[], text[])'::regprocedure,
            '32BUI',
            'CUSTOM', t1.rast,
            1, 1
        ) AS rast
    FROM src t1
    JOIN foo t2
        ON t1.rid = t2.rid
)
SELECT
    rid,
    (ST_Metadata(rast)),
    (ST_BandMetadata(rast, 1)),
    ST_Value(rast, 1, 1, 1)
FROM bar;

示例：变体2和3

一个栅格，多个波段

WITH foo AS (
    SELECT 1 AS rid, ST_AddBand(ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, 0, 1, -1, 0, 0, 0), 1, '16BUI', 1, 0), 2, '8BUI', 10, 0), 3, '32BUI', 100, 0) AS rast
)
SELECT
    ST_MapAlgebra(
        rast, ARRAY[3, 1, 3, 2]::integer[],
        'sample_callbackfunc(double precision[], int[], text[])'::regprocedure
    ) AS rast
FROM foo

一个栅格，一个波段

WITH foo AS (
    SELECT 1 AS rid, ST_AddBand(ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, 0, 1, -1, 0, 0, 0), 1, '16BUI', 1, 0), 2, '8BUI', 10, 0), 3, '32BUI', 100, 0) AS rast
)
SELECT
    ST_MapAlgebra(
        rast, 2,
        'sample_callbackfunc(double precision[], int[], text[])'::regprocedure
    ) AS rast
FROM foo

示例：变体4

两个栅格，两个波段

WITH foo AS (
    SELECT 1 AS rid, ST_AddBand(ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, 0, 1, -1, 0, 0, 0), 1, '16BUI', 1, 0), 2, '8BUI', 10, 0), 3, '32BUI', 100, 0) AS rast UNION ALL
    SELECT 2 AS rid, ST_AddBand(ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, 1, 1, -1, 0, 0, 0), 1, '16BUI', 2, 0), 2, '8BUI', 20, 0), 3, '32BUI', 300, 0) AS rast
)
SELECT
    ST_MapAlgebra(
        t1.rast, 2,
        t2.rast, 1,
        'sample_callbackfunc(double precision[], int[], text[])'::regprocedure
    ) AS rast
FROM foo t1
CROSS JOIN foo t2
WHERE t1.rid = 1
    AND t2.rid = 2

示例：使用蒙版

WITH foo AS (SELECT
   ST_SetBandNoDataValue(
ST_SetValue(ST_SetValue(ST_AsRaster(
        ST_Buffer(
            ST_GeomFromText('LINESTRING(50 50,100 90,100 50)'), 5,'join=bevel'),
            200,200,ARRAY['8BUI'], ARRAY[100], ARRAY[0]), ST_Buffer('POINT(70 70)'::geometry,10,'quad_segs=1') ,50),
  'LINESTRING(20 20, 100 100, 150 98)'::geometry,1),0)  AS rast )
SELECT 'original' AS title, rast
FROM foo
UNION ALL
SELECT 'no mask mean value' AS title, ST_MapAlgebra(rast,1,'ST_mean4ma(double precision[], int[], text[])'::regprocedure) AS rast
FROM foo
UNION ALL
SELECT 'mask only consider neighbors, exclude center' AS title, ST_MapAlgebra(rast,1,'ST_mean4ma(double precision[], int[], text[])'::regprocedure,
    '{{1,1,1}, {1,0,1}, {1,1,1}}'::double precision[], false) As rast
FROM foo

UNION ALL
SELECT 'mask weighted only consider neighbors, exclude center multi otehr pixel values by 2' AS title, ST_MapAlgebra(rast,1,'ST_mean4ma(double precision[], int[], text[])'::regprocedure,
    '{{2,2,2}, {2,0,2}, {2,2,2}}'::double precision[], true) As rast
FROM foo;

原创

无掩码平均值(与掩码矩阵中全为1相同)

掩码仅考虑邻居，排除中心

遮罩加权仅考虑邻域，将中心多个其他像素值排除2

另请参阅

粗制滥造 , ST_Union , ST_MapAlgebra(表达式版本)