[gdal-dev] How to divide a raster layer into a set of tiles?

[Gilles Bassière]

Even Rouault wrote:
> Le Monday 22 March 2010 19:35:47 Gilles Bassière, vous avez écrit :
>> Hi,
>>
>> The problem with this workflow is that it creates non-georeferenced
>> tiles (I don't know if this is the intended behaviour of this command).
> 
> gdal_retile.py *does* create georeferenced tiles. I've just verified it. What 
> make you think the contrary ?
> 
> 

I created the new tile set with this command:
$ gdal_retile.py -targetDir $DATA_OUT/ -ps 10000 10000 -of ECW
$DATA/ortho-dept04-2004-lam93.vrt

and if I run gdalinfo on one of the resulting tiles, I get:
$ gdalinfo $DATA_OUT/ortho-dept04-2004-lam93_04_08.ecw
Driver: ECW/ERMapper Compressed Wavelets
Files:
/home/gilux/Data/ortho-dept04-2004-lam93/ortho-dept04-2004-lam93_04_08.ecw

/home/gilux/Data/ortho-dept04-2004-lam93/ortho-dept04-2004-lam93_04_08.ecw.aux.xml
Size is 10000, 10000
Coordinate System is:
PROJCS["unnamed",
    GEOGCS["GRS 1980(IUGG, 1980)",
        DATUM["unknown",
            SPHEROID["GRS80",6378137,298.257222101],
            TOWGS84[0,0,0,0,0,0,0]],
        PRIMEM["Greenwich",0],
        UNIT["degree",0.0174532925199433]],
    PROJECTION["Lambert_Conformal_Conic_2SP"],
    PARAMETER["standard_parallel_1",49],
    PARAMETER["standard_parallel_2",44],
    PARAMETER["latitude_of_origin",46.5],
    PARAMETER["central_meridian",3],
    PARAMETER["false_easting",700000],
    PARAMETER["false_northing",6600000],
    UNIT["Meter",1]]
Corner Coordinates:
Upper Left  (    0.0,    0.0)
Lower Left  (    0.0,10000.0)
Upper Right (10000.0,    0.0)
Lower Right (10000.0,10000.0)
Center      ( 5000.0, 5000.0)
Band 1 Block=10000x1 Type=Byte, ColorInterp=Red
  Overviews: arbitrary
Band 2 Block=10000x1 Type=Byte, ColorInterp=Green
  Overviews: arbitrary
Band 3 Block=10000x1 Type=Byte, ColorInterp=Blue
  Overviews: arbitrary

The tiles are actually georeferenced but pixel coordinates are used. For
every tile, the corner coordinates are the same and it corresponds to
the -ps option.

-- 
Gilles Bassière - Web/GIS software engineer
http://gbassiere.free.fr/