afni.nimh.nih.gov

In follow-up with this question:

In looking at the files, the error message was due to the fact that the network file ('1.nii.gz') was not composed of integer-valued targets, but instead islands of floating point values. A quick run through 3dROIMaker:

$ 3dROIMaker -inset 1.nii.gz -prefix ROIS -nifti

sorted this out, so that the following ran without error, yielding tracts:

3dTrackID -mode DET -dti_in dti -netrois ROIS_GM.nii.gz -logic OR -prefix output_1

--pt