MrSID files
MrSID is a proprietary compressed image file format of [LizardTech] It has become very popular for GIS files, especially orthophotos because it is efficient and lossless.
It is proprietary so it's not supported in GRASS.
But all is not lost! The kindly folk at LizardTech supply a free decoder. It is available for Windows, Linux and Solaris. It will convert MrSID images to JPG, GeoTIFF image formats. It can also scale images, extract part of an image, and a few other things...
Go to the downloads area at the LizardTech site and look for "MrSID Decode"
For example, to convert a Corvallis orthophoto to a GeoTIFF
mrsiddecode -of tifg -i 11s5w15f_color_sw.sid -o ~/workspace/11s5w15f_color_sw.tif
The "-of tifg" tells it to generate a GeoTIFF not just a plain image TIFF. By default it will give a progress indicator. You can turn this off if you want. Output for the above command looked like this:
mrsiddecode: (c) 2004 LizardTech, Inc. All rights reserved. input: width: 5501 height: 6200 upper-left X: 1273797.814000 upper-left Y: 358042.349000 X scale: 0.500000 Y scale: -0.500000 output: width: 5501 height: 6200 upper-left X: 1273797.814000 upper-left Y: 358042.349000 X scale: 0.500000 Y scale: -0.500000 format: GeoTIFF