ST_Raster.describe
定义
ST_Raster describe 用于提供 ST_Raster 对象的属性列表。可选输入参数包括 storage（指示 describe 函数按金字塔等级显示每个波段的存储大小）或 color map（指示 describe 函数在存在色彩映射表索引时将其列出）。describe 函数被设计作为 SQL SELECT 语句的选择列表的一部分以独占方式运行。
语法
Oracle
describe () RETURN CLOB describe (parameter IN VARCHAR2) RETURN CLOB
PostgreSQL
describe (raster IN ST_RASTER) RETURN TEXT
describe (raster IN ST_RASTER,
parameter IN TEXT) RETURN TEXT
SQL Server
describe (parameter IN NVARCHAR) RETURN NVARCHAR
返回值
CLOB
参数
如果没有提供参数，describe 函数会显示 ST_Raster 对象的基本属性。
参数 | 描述 |
|---|---|
storage | 指示 describe 函数列出色彩映射的 ST_Raster 对象的每个波段和金字塔等级的实际压缩存储位移 |
colormap | 指示 describe 函数列出色彩映射的 ST_Raster 对象的色彩映射表索引 |
示例
这些示例演示了以下内容：
- 第一个示例是 SELECT 语句，它提供了来自 ST_Raster.describe() 函数的 ST_Raster 属性的列表。
- 下一个示例说明了如果通过 ST_Raster.describe() 函数使用存储参数。
- 最后一个示例显示了如何返回栅格色彩映射表信息。
Oracle
-
SELECT n.image.describe() FROM NOVA n; Raster ID ...................: 2 Raster Column ID ............: 268 Raster Dimension ............: 6000, 6000, 1 Raster Tile Dimension .......: 128, 128 Pixel Type ..................: int16 Compression .................: lz77 Image Pyramid ...............: 6, bilinear Extent ......................: <NONE> Statistics ..................: min : 4271.0000000000 max : 6751.0000000000 mean : 5024.6673817222 std dev : 272.5172958117
-
SELECT n.image.describe('storage') FROM NOVA n; Raster Tile Storage .........: min max mean std dev count total Level 0: Band 1 61 23802 16818.32 3681.83 2209 36,281 KB Level 1: Band 1 2506 24028 17958.37 3836.54 576 10,102 KB Level 2: Band 1 6786 23245 19566.38 2732.57 144 2,752 KB Level 3: Band 1 16547 23232 20919.81 1736.37 36 735 KB Level 4: Band 1 19764 23620 21993.11 1271.31 9 193 KB Level 5: Band 1 5854 23853 13186.50 7596.00 4 52 KB Level 6: Band 1 13563 13563 13563.00 0.00 1 13 KB 50,128 KB 51,330,596 bytes Compression Ratio ...........: 1.40267 -
SELECT n.image.describe('colormap') FROM NOVA n WHERE n.image.raster_id = 1; Raster ID ...................: 1 Raster Column ID ............: 329 Raster Dimension ............: 512, 512, 1 Raster Tile Dimension .......: 128, 128 Pixel Type ..................: uint8 Compression .................: lz77 Image Pyramid ...............: <NONE> Extent ......................: <NONE> Colormap ....................: rgb, uint16, 256 index red green blue 0 14906 0 0 1 8738 0 0 2 5654 0 0 3 2570 0 0 4 27242 23901 31868 5 51143 50886 51400 6 19018 13878 23644 7 6168 2056 6168 8 55512 51400 55512 9 63736 59624 63736 10 60138 55512 59624 ... ... ... ... 250 63736 63736 63736 251 59624 59624 59624 252 55512 55512 55512 253 6168 6168 6168 254 2056 2056 2056 255 65535 65535 65535
PostgreSQL
-
SELECT describe(image) FROM nova; Raster ID ...................: 2 Raster Column ID ............: 268 Raster Dimension ............: 6000, 6000, 1 Raster Tile Dimension .......: 128, 128 Pixel Type ..................: int16 Compression .................: lz77 Image Pyramid ...............: 6, bilinear Extent ......................: <NONE> Statistics ..................: min : 4271.0000000000 max : 6751.0000000000 mean : 5024.6673817222 std dev : 272.5172958117
-
SELECT describe(image,'storage') FROM nova; Raster Tile Storage .........: min max mean std dev count total Level 0: Band 1 61 23802 16818.32 3681.83 2209 36,281 KB Level 1: Band 1 2506 24028 17958.37 3836.54 576 10,102 KB Level 2: Band 1 6786 23245 19566.38 2732.57 144 2,752 KB Level 3: Band 1 16547 23232 20919.81 1736.37 36 735 KB Level 4: Band 1 19764 23620 21993.11 1271.31 9 193 KB Level 5: Band 1 5854 23853 13186.50 7596.00 4 52 KB Level 6: Band 1 13563 13563 13563.00 0.00 1 13 KB 50,128 KB 51,330,596 bytes Compression Ratio ...........: 1.40267 -
SELECT describe(image,'colormap') FROM nova WHERE image.raster_id = 1; Raster ID ...................: 1 Raster Column ID ............: 329 Raster Dimension ............: 512, 512, 1 Raster Tile Dimension .......: 128, 128 Pixel Type ..................: uint8 Compression .................: lz77 Image Pyramid ...............: <NONE> Extent ......................: <NONE> Colormap ....................: rgb, uint16, 256 index red green blue 0 14906 0 0 1 8738 0 0 2 5654 0 0 3 2570 0 0 4 27242 23901 31868 5 51143 50886 51400 6 19018 13878 23644 7 6168 2056 6168 8 55512 51400 55512 9 63736 59624 63736 10 60138 55512 59624 ... ... ... ... 250 63736 63736 63736 251 59624 59624 59624 252 55512 55512 55512 253 6168 6168 6168 254 2056 2056 2056 255 65535 65535 65535
SQL Server
-
SELECT image.describe(NULL) FROM nova; Raster ID ...................: 2 Raster Column ID ............: 268 Raster Dimension ............: 6000, 6000, 1 Raster Tile Dimension .......: 128, 128 Pixel Type ..................: int16 Compression .................: lz77 Image Pyramid ...............: 6, bilinear Extent ......................: <NONE> Statistics ..................: min : 4271.0000000000 max : 6751.0000000000 mean : 5024.6673817222 std dev : 272.5172958117
-
SELECT image.describe('storage') FROM nova; Raster Tile Storage .........: min max mean std dev count total Level 0: Band 1 61 23802 16818.32 3681.83 2209 36,281 KB Level 1: Band 1 2506 24028 17958.37 3836.54 576 10,102 KB Level 2: Band 1 6786 23245 19566.38 2732.57 144 2,752 KB Level 3: Band 1 16547 23232 20919.81 1736.37 36 735 KB Level 4: Band 1 19764 23620 21993.11 1271.31 9 193 KB Level 5: Band 1 5854 23853 13186.50 7596.00 4 52 KB Level 6: Band 1 13563 13563 13563.00 0.00 1 13 KB 50,128 KB 51,330,596 bytes Compression Ratio ...........: 1.40267 -
SELECT image.describe('colormap') FROM nova WHERE image.raster_id = 1; Raster ID ...................: 1 Raster Column ID ............: 329 Raster Dimension ............: 512, 512, 1 Raster Tile Dimension .......: 128, 128 Pixel Type ..................: uint8 Compression .................: lz77 Image Pyramid ...............: <NONE> Extent ......................: <NONE> Colormap ....................: rgb, uint16, 256 index red green blue 0 14906 0 0 1 8738 0 0 2 5654 0 0 3 2570 0 0 4 27242 23901 31868 5 51143 50886 51400 6 19018 13878 23644 7 6168 2056 6168 8 55512 51400 55512 9 63736 59624 63736 10 60138 55512 59624 ... ... ... ... 250 63736 63736 63736 251 59624 59624 59624 252 55512 55512 55512 253 6168 6168 6168 254 2056 2056 2056 255 65535 65535 65535
7/10/2012