ST_PixelAsCentroids
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Name

ST_PixelAsCentroids — 返回栅格波段的每个像素的质心（点几何）以及每个像素的值、X 和 Y 栅格坐标。 点几何是像素表示的区域的质心。

Synopsis

setof record ST_PixelAsCentroids(raster rast, integer band=1, boolean exclude_nodata_value=TRUE);

描述

返回栅格波段的每个像素的质心（点几何）以及每个像素的值、X 和 Y 栅格坐标。 点几何是像素表示的区域的质心。

返回记录格式：geom geometry，val双精度，x整数，y整数。

[Note]

当 except_nodata_value = TRUE 时，仅将那些值不是 NODATA 的像素作为点返回。

增强：3.2.0 Faster 现在用 C 实现。

更改：2.1.1 更改了 except_nodata_value 的行为。

可用性：2.1.0

示例

--LATERAL syntax requires PostgreSQL 9.3+
SELECT x, y, val, ST_AsText(geom)
    FROM (SELECT dp.* FROM dummy_rast, LATERAL ST_PixelAsCentroids(rast, 1) AS dp WHERE rid = 2) foo;
 x | y | val |           st_astext
---+---+-----+--------------------------------
 1 | 1 | 253 | POINT(3427927.775 5793243.975)
 2 | 1 | 254 | POINT(3427927.825 5793243.975)
 3 | 1 | 253 | POINT(3427927.875 5793243.975)
 4 | 1 | 254 | POINT(3427927.925 5793243.975)
 5 | 1 | 254 | POINT(3427927.975 5793243.975)
 1 | 2 | 253 | POINT(3427927.775 5793243.925)
 2 | 2 | 254 | POINT(3427927.825 5793243.925)
 3 | 2 | 254 | POINT(3427927.875 5793243.925)
 4 | 2 | 253 | POINT(3427927.925 5793243.925)
 5 | 2 | 249 | POINT(3427927.975 5793243.925)
 1 | 3 | 250 | POINT(3427927.775 5793243.875)
 2 | 3 | 254 | POINT(3427927.825 5793243.875)
 3 | 3 | 254 | POINT(3427927.875 5793243.875)
 4 | 3 | 252 | POINT(3427927.925 5793243.875)
 5 | 3 | 249 | POINT(3427927.975 5793243.875)
 1 | 4 | 251 | POINT(3427927.775 5793243.825)
 2 | 4 | 253 | POINT(3427927.825 5793243.825)
 3 | 4 | 254 | POINT(3427927.875 5793243.825)
 4 | 4 | 254 | POINT(3427927.925 5793243.825)
 5 | 4 | 253 | POINT(3427927.975 5793243.825)
 1 | 5 | 252 | POINT(3427927.775 5793243.775)
 2 | 5 | 250 | POINT(3427927.825 5793243.775)
 3 | 5 | 254 | POINT(3427927.875 5793243.775)
 4 | 5 | 254 | POINT(3427927.925 5793243.775)
 5 | 5 | 254 | POINT(3427927.975 5793243.775)