Name
ST_PixelAsCentroids — 返回栅格标注栏的每个像素的质心(点几何图形)以及每个像素的值、X和Y栅格坐标。点几何图形是由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
返回栅格标注栏的每个像素的质心(点几何图形)以及每个像素的值、X和Y栅格坐标。点几何图形是由像素表示的区域的质心。
Return record format:
geom
几何体
,
val
double precision,
x
integer,
y
integers.
![[Note]](images/note.png)
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什么时候
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增强：现在在C语言中实现的速度提高了3.2.0。
已更改：2.1.1更改了EXCLUDE_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)