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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：

  1. 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。
  2. 下一个示例说明了如果通过 ST_Raster.describe() 函数使用存储参数。
  3. 最后一个示例显示了如何返回栅格色彩映射表信息。

Oracle

  1. 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

  2. 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

  3. 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

  1. 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

  2. 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

  3. 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

  1. 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

  2. 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

  3. 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