| 311 | | || '''version''' || WKB format version (now 0). || unsigned 16 bit integer || Not accessible. || |
| 312 | | || '''number of bands''' || Number of raster bands stored in the raster. || unsigned 16 bit integer || ST_NumBands() || |
| 313 | | || '''width''' || Width of the raster. || unsigned 16 bit integer || ST_Width() || |
| 314 | | || '''height''' || Height of the raster. || unsigned 16 bit integer || ST_Height() || |
| | 311 | || version || WKB format version (now 0). || unsigned 16 bit integer || Not accessible. || |
| | 312 | || number of bands || Number of raster bands stored in the raster. || unsigned 16 bit integer || ST_NumBands() || |
| | 313 | || width || Width of the raster. || unsigned 16 bit integer || ST_Width() || |
| | 314 | || height || Height of the raster. || unsigned 16 bit integer || ST_Height() || |
| 316 | | || '''pixelsizex''' || Pixel size in the x-direction in the same map units as the coordinate system. Same as parameter A in a world file. || 64 bit double || ST_PixelSizeX() || |
| 317 | | || '''pixelsizey''' || Pixel size in the y-direction in the same map units as the coordinate system. Same as parameter E in a world file. || 64 bit double || ST_PixelSizeY() || |
| 318 | | || '''upperleftx''' || X-coordinate of the center of the upper left pixel. Same as parameter C in a world file. || 64 bit double || ST_UpperLeftX() || |
| 319 | | || '''upperlefty''' || Y-coordinate of the center of the upper left pixel. Same as parameter F in a world file. || 64 bit double || ST_UpperLeftY() || |
| 320 | | || '''rotationx''' || Rotation about x-axis. Same as parameter B in a world file. || 64 bit double || ST_RotationX() || |
| 321 | | || '''rotationy''' || Rotation about y-axis. Same as parameter D in a world file. || 64 bit double || ST_RotationY() || |
| 322 | | || '''srid''' || Spatial reference id. || 32 bit integer || ST_SRID() || |
| | 316 | || pixelsizex || Pixel size in the x-direction in the same map units as the coordinate system. Same as parameter A in a world file. || 64 bit double || ST_PixelSizeX() || |
| | 317 | || pixelsizey || Pixel size in the y-direction in the same map units as the coordinate system. Same as parameter E in a world file. || 64 bit double || ST_PixelSizeY() || |
| | 318 | || upperleftx || X-coordinate of the center of the upper left pixel. Same as parameter C in a world file. || 64 bit double || ST_UpperLeftX() || |
| | 319 | || upperlefty || Y-coordinate of the center of the upper left pixel. Same as parameter F in a world file. || 64 bit double || ST_UpperLeftY() || |
| | 320 | || rotationx || Rotation about x-axis. Same as parameter B in a world file. || 64 bit double || ST_RotationX() || |
| | 321 | || rotationy || Rotation about y-axis. Same as parameter D in a world file. || 64 bit double || ST_RotationY() || |
| | 322 | || srid || Spatial reference id. || 32 bit integer || ST_SRID() || |
| 324 | | || '''isoffline''' || Flag specifying if the band data is stored in the database or as a file in the file system. || 1 bit || If ST_BandPath() return an empty string, the data is stored in the database. || |
| 325 | | || '''hasnodatavalue''' || Flag specifying if the stored nodatavalue is significant or not. || 1 bit || ST_BandHasNoDataValue() || |
| 326 | | || '''pixeltype''' || Pixel type for this band. || 4 bits || ST_BandPixelType() || |
| 327 | | || '''nodatavalue''' || Nodata value for the band. || Depend on band pixel type. || ST_BandNodataValue() || |
| | 324 | || isoffline || Flag specifying if the band data is stored in the database or as a file in the file system. || 1 bit || If ST_BandPath() return an empty string, the data is stored in the database. || |
| | 325 | || hasnodatavalue''' || Flag specifying if the stored nodatavalue is significant or not. || 1 bit || ST_BandHasNoDataValue() || |
| | 326 | || pixeltype || Pixel type for this band. || 4 bits || ST_BandPixelType() || |
| | 327 | || nodatavalue || Nodata value for the band. || Depend on band pixel type. || ST_BandNodataValue() || |
| 331 | | || '''bandnumber''' || Number of the out-db band. || unsigned 8 bit integer || Not accessible yet. || |
| 332 | | || '''path''' || Path to the out-db raster file. || string || ST_BandPath() || |
| 333 | | |
| | 331 | || bandnumber || Number of the out-db band. || unsigned 8 bit integer || Not accessible yet. || |
| | 332 | || path || Path to the out-db raster file. || string || ST_BandPath() || |
| | 333 | |
| | 334 | Min and max values for: |
| | 335 | |
| | 336 | * "unsigned 8 bits integer" are 0 and 255. |
| | 337 | * "unsigned 16 bits integer" are 0 and 65535. |
| | 338 | * "32 bits integer" are -2 147 483 648 and 2 147 483 647. |
| | 339 | * "64 bits double" are -1.7*10-308 and 1.7*10308. |
| | 340 | |
| | 341 | PostGIS WKT Raster is expressed in different forms, depending on the level at which it is referred: |
| | 342 | |
| | 343 | * '''WKT -''' "Well Known Text" refers to the human readable text format used when inserting a raster with ST_RasterFromText() (not yet implemented) and retrieving a raster with ST_AsText() (not yet implemented). This format can result in the loss of precision when used with floating point values. This is why the HEXWKB form is preferred when importing/exporting in textual form. |
| | 344 | |
| | 345 | * '''WKB -''' "Well Known Binary" refers to the binary equivalent of the WKT. It is used when inserting a raster using ST_RasterFromWKB() and retrieving a raster using ST_AsBinary(). |
| | 346 | |
| | 347 | * '''HEXWKB -''' "Hexadecimal WKB" is an exact hexadecimal representation of the WKB form. It is also called the "canonical" form. It is what you get from the loader (gdal2wktraster.py), what is accepted by the raster type input function (ST_Raster_In), and what you get when outputting the value of a raster field without conversion (e.g. SELECT rast FROM table). |
| | 348 | |
| | 349 | * '''Serialized -''' The "serialized" format is what is written to the filesystem by the database. It differs from WKB in that it does not have to store the endianness of the data and that it must be aligned. Serializing is the action of writing data to the database file, deserializing is the action of reading this data. |
| | 350 | |
| | 351 | '''The raster_columns Table''' |
| | 352 | |
| | 353 | Like the PostGIS "geometry_column" table, the PostGIS WKT Raster "raster_columns" table is a way for applications to get a quick overview of which tables have a raster column, and to get the main characteristics (metadata) of the rasters stored in these columns. Applications should maintain this table using the AddRasterColumn() and DropRasterColumn() functions, as there is no automatic mechanism in the database to keep this table up to date with every raster column created or deleted. |
| | 354 | |
| | 355 | Table 3 summarizes the attributes of the raster_columns table. |
