On 9/22/05, John Ashburner <[log in to unmask]> wrote:

Dear Stephan,
I'm afraid that there is no option to do this, although the NIfTI utilities
within SPM would allow it to be done.  My choice of using the dual file
system was based on the FIL having an automated backup system.  Having a
separate .hdr and .img would mean that only the .hdr files would be backed up
after tweeks are made to the headers (e.g. after realignment), which I
figured would save us a lot of tape.

I also chose to not work directly with gzipped data - mostly because of
lazyness.  The .gz files would also make a number of routines slower.  For
example, if you just want to read a single voxel in a file, then all the data
before that voxel would need to be uncompressed.

The AFNI developers are part of the Data Format Working Group who developed
NIfTI, so I'm surprised that AFNI doesn't deal with the .hdr+.img format.

Best regards,
-John

> Is there an option in SPM5b (or the upcoming SPM5) to output to the
> single-file (.nii) NIfTI-1 format?
>
> I can output to the dual-file (.hdr & .img) format but I would really
> like to interchange with AFNI, which needs the single-file .nii
> or .nii.gz format. Concatenating the SPM5b dual-files using the FSL
> tools (avwmerge) resulted in an error.