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ST_Raster.describe

Definition

ST_Raster.describe provides the property list of an ST_Raster object. Optional input parameters include either storage, which directs the describe function to display the storage size of each band by pyramid level, or color map, which indicates that the describe function should list the color map index if one exists. The describe function has been designed to operate exclusively as part of the select list of a SQL SELECT statement.

Syntax

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

Returns

CLOB

Parameters

If a parameter is not provide, the describe function displays basic properties of the ST_Raster object.

ParameterDescription

storage

Directs the describe function to list the actual compressed storage displacement for each band and pyramid level of the color-mapped ST_Raster object

colormap

Directs the describe function to list the color map index of the color-mapped ST_Raster object

Examples

These examples demonstrate the following:

  1. The first example is a SELECT statement and provides a list of ST_Raster properties from the ST_Raster.describe() function.
  2. The next example illustrates the use of the storage parameter with the ST_Raster.describe() function.
  3. The last example shows you how to return the raster color map information.

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