Hi Rob,
I wanted to add a few pieces of additional information here just in case they help with troubleshooting.
The misbehaviour of tckresample does not appear to be isolated to the -arc option. The -line option appears to have the same results as the images presented in the previous post.
Also, while the output file does contain the requested 20 samples, it does have some “ragged edges”. I initially attributed this to the fact that some of the streamlines may have not quite made it to the end of the sampling area. However, in this post (Coordinates for tckresample…) it clearly states that only streamlines that span the entire path will be sampled therefore there should be no “ragged edges” in the data file.
In this example below I asked for 10 samples along a line and the resulting data file has 9 or 10 values in any given row and some rows are shifted to the right. Could this possibly help to diagnose the misbehaviour of tckresample?
Thanks very much
Helen