[postgis-devel] [WKT Raster] Regular blocking and null extent

[Pierre Racine]

>>>>> Shall we allow generation of regular blocking tables
>>>> >from non-georeferenced datasets reported by GDAL as follows:
>>>>> $ gdalinfo chessboard-64x64.tif
>>>>> Driver: GTiff/GeoTIFF
>>>>> Files: chessboard-64x64.tif
>>>>> Size is 64, 64
>>>>> Coordinate System is `'
>>>>> Metadata:
>>>>>  TIFFTAG_DOCUMENTNAME=/home/mloskot/data/test/sample/chessboard-64x64.tif
>>>>>  TIFFTAG_IMAGEDESCRIPTION=Sample 4-fields greyscale chessboard
>>>>>  TIFFTAG_XRESOLUTION=72
>>>>>  TIFFTAG_YRESOLUTION=72
>>>>>  TIFFTAG_RESOLUTIONUNIT=2 (pixels/inch)
>>>>> Image Structure Metadata:
>>>>>  INTERLEAVE=BAND
>>>>> Corner Coordinates:
>>>>> Upper Left  (    0.0,    0.0)
>>>>> Lower Left  (    0.0,   64.0)
>>>>> Upper Right (   64.0,    0.0)
>>>>> Lower Right (   64.0,   64.0)
>>>>> Center      (   32.0,   32.0)
>>>>> Band 1 Block=64x64 Type=Byte, ColorInterp=Gray
>>>>>
>>>>> and assume pixelsize_x = 1 and pixelsize_y = -1 ?
>>>> That's what I would do also. There is an extent but no (geographical)
>>>> coordinate system. That's what ArcGIS does when importing an ungeoreferenced
>>>> raster.
>>> Givne what GDAL reports for chessboard-64x64.tif, could you explain
>>> what values you put into RASTER header in each row (tile) and
>>> what goes to RASTER_COLUMNS, etc.?
>>
>> In the raster header (there should be only one tile, right?):
>>
>> scaleX = 1
>> scaleY = -1
>> ipX = 0.0
>> ipY = 0.0
>> skewX = 0.0
>> skewY = 0.0
>> srid = -1 (or 0?)
>> width = 64
>> height = 64
>>
>> In RASTER_COLUMNS:
>>
>> srid = -1 (or 0?)
>> pixel_types = 8BUI
>> regular_blocking = true
>> pixelsize_x = 1.0
>> pixelsize_y = -1.0
>> blocksize_x = 64
>> blocksize_y = 64
>>
>> No?
>
>What's in the extent field of RASTER_COLUMNS?

It would be: ST_GeomFromEWKT('SRID=-1;POLYGON(0.0 0.0, 0.0 64.0, 64.0 64.0, 64.0 0.0, 0.0 0.0)')

Pierre