Name
ST_BandMetaData — 返回特定栅格波段的基本元数据。如果未指定，则假定波段编号为1。
Synopsis
(1) record
ST_BandMetaData
(
raster
rast
, integer
band=1
)
;
(2) record
ST_BandMetaData
(
raster
rast
, integer[]
band
)
;
描述
返回有关栅格标注栏的基本元数据。返回的列：象素类型、nodatavalue、isoutdb、路径、outdbband num、文件大小、文件时间戳。
![[Note]](images/note.png)
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如果栅格不包含波段，则会引发错误。 |
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如果BAND没有NODATA值，则nodatavue为空。 |
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如果isoutdb为FALSE，则路径、outDBband num、文件大小和文件时间戳为空。如果禁用outdb访问，则文件大小和文件时间戳也将为空。 |
增强版：2.5.0以包括 输出数据库带宽 ， 文件大小 和 文件时间戳 用于outdb栅格。
示例：变体1
SELECT
rid,
(foo.md).*
FROM (
SELECT
rid,
ST_BandMetaData(rast, 1) AS md
FROM dummy_rast
WHERE rid=2
) As foo;
rid | pixeltype | nodatavalue | isoutdb | path | outdbbandnum
-----+-----------+---- --------+---------+------+--------------
2 | 8BUI | 0 | f | |
示例：变体2
WITH foo AS (
SELECT
ST_AddBand(NULL::raster, '/home/pele/devel/geo/postgis-git/raster/test/regress/loader/Projected.tif', NULL::int[]) AS rast
)
SELECT
*
FROM ST_BandMetadata(
(SELECT rast FROM foo),
ARRAY[1,3,2]::int[]
);
bandnum | pixeltype | nodatavalue | isoutdb | path | outdbbandnum | filesize | filetimestamp |
---------+-----------+-------------+---------+--------------------------------------------------------------------------------+---------------+----------+---------------+-
1 | 8BUI | | t | /home/pele/devel/geo/postgis-git/raster/test/regress/loader/Projected.tif | 1 | 12345 | 1521807257 |
3 | 8BUI | | t | /home/pele/devel/geo/postgis-git/raster/test/regress/loader/Projected.tif | 3 | 12345 | 1521807257 |
2 | 8BUI | | t | /home/pele/devel/geo/postgis-git/raster/test/regress/loader/Projected.tif | 2 | 12345 | 1521807257 |