ST_PixelHeight
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名称

ST_PixelHeight — 返回空间参考系统的几何单位的像素高度。

大纲

double precision ST_PixelHeight(raster rast);

Description

以空间参考系统的几何单位返回像素的高度。 在没有倾斜的常见情况下，像素高度只是几何坐标与光栅像素之间的比例。

请参阅 ST_PixelWidth 以直观地了解该关系。

示例

Rasters with no skew.

Code
SELECT ST_Height(rast) As rastheight, ST_PixelHeight(rast) As pixheight,
 ST_ScaleX(rast) As scalex, ST_ScaleY(rast) As scaley, ST_SkewX(rast) As skewx,
        ST_SkewY(rast) As skewy
FROM dummy_rast;
栅格输出
rastheight | pixheight | scalex | scaley | skewx | skewy
------------+-----------+--------+--------+-------+----------
         20 |         3 |      2 |      3 |     0 |        0
          5 |      0.05 |   0.05 |  -0.05 |     0 |        0

Rasters with skew different than 0.

Code
SELECT ST_Height(rast) As rastheight, ST_PixelHeight(rast) As pixheight,
 ST_ScaleX(rast) As scalex, ST_ScaleY(rast) As scaley, ST_SkewX(rast) As skewx,
        ST_SkewY(rast) As skewy
FROM (SELECT ST_SetSkew(rast, 0.5, 0.5) As rast
        FROM dummy_rast) As skewed;
栅格输出
rastheight |     pixheight     | scalex | scaley | skewx | skewy
-----------+-------------------+--------+--------+-------+----------
        20 |  3.04138126514911 |      2 |      3 |   0.5 |      0.5
         5 | 0.502493781056044 |   0.05 |  -0.05 |   0.5 |      0.5