[Gvsig_english] Georeferencing MrSID (.sid) format image

[Antonio Falciano]

Payne Denis ha scritto:
> I have 4 large .sid format images I need to load. They are 12.5cm
> resolution aerial photography each covering 5km*5km. I'm working in UK
> Nat Grid, and using gvsig 1.1.2
> 
> They open OK - but not properly position. They show as being at the
> origin. I have tried georeferencing them - but whilst the process
> appears OK that doesn't appear to solve the problem. I have what looks
> like a valid .rmf file from that process.
> 
> I've tried using IrfranView to convert to .jpg format, but that doesn't
> retain the resolution of the original .sid format images.
> 
> I'd welcome any suggestions as to how I can get these, at full
> resolution, properly positioned, into gvsig

Hi Denis,
you can convert them into another format using GDAL:
http://www.gdal.org/gdal_translate.html

The explanation of this apparently strange behaviour is that...

>> The key point here its: if the files are geospatial ones (geotiff and
>> MrSID), gvSIG will use the internal information. If they are no
>> geospatial ones (standard tiff and jpeg, by instance) gvSIG will use
>> external world files as this is the only way to georeferencing them 
from http://www.nabble.com/Re%3A-Problemi-con-file-MrSID-p15484600.html

Regards,
Antonio