[gdal-dev] Altering the GeoTransform matrix with World files and VRT files

[Frank Warmerdam]

Craig,

The mechanism that Jukka mentions is MapServer-only.
Reviewing the code, it appears that shapefiles are still
just a fallback if no georeferencing is found internally.

I am not aware of software for overriding mrsid georeferencing
in the file.

Best regards,

On Tue, Jan 26, 2010 at 8:42 PM, Craig Leat <craig.leat at gmail.com> wrote:
> Hi,
>
> I have a collection of MrSid images with embedded georeferencing
> information and accompanying world files. The world files have correct
> geotransform values, but the information embedded in the sid files is
> incorrect. My installation of gdal 1.7 gives precedence to the
> embedded georeferencing over the world file. Based on this mail [1], I
> understand that this order of precedence was a gdal design decision
> and I need to use a vrt file to alter the geotransform. Since I have
> many files and I don't expect that the government supplier will
> correct the data for me I have started writing a script to generate
> the vrt files and then alter the geotransform in the vrt based on
> values found in the world file.
>
> Before I proceed much further I wish to pose two questions:
> 1. Is there a gdal environment variable I may have missed that can be
> used to give precedence to the world file?
> 2. Is there any freely available software that will modify the
> metadata tags in a sid file?
>
> PS I would rather not translate from sid to tif.
>
> Much thanks,
>
> Craig
>
> [1] http://n2.nabble.com/Georeferencing-Mrsid-raster-file-with-a-world-file-td1994277.html#a1994280
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