Hi Sarah

It is something like:

100 * (mean(abs(distance error)) / mean(original_distances))

Cheers Bruce

From: freesurfer-bounces@nmr.mgh.harvard.edu freesurfer-bounces@nmr.mgh.harvard.edu On Behalf Of Sarah Lavelle Sent: Tuesday, November 8, 2022 12:20 PM To: freesurfer@nmr.mgh.harvard.edu Subject: [Freesurfer] Calculating Distortion in mris_flatten()

External Email - Use Caution Hi freesurfers,

Does anyone know how to measure the distortion of your inflated surface -> flatmap transformation (using mris_flatten)?

When being run, the function outputs "final distance error ...%" in the terminal. What exactly does this mean? and how is this calculated?

I would like to research optimal cuts for flatmaps, depending on the region of interest (ROI), so we can minimize the distortion of the ROI itself on the 2D map. If anyone has any ideas on how this can be done or is interested in working with me on this, please contact me via <lavells1@tcd.iemailto:lavells1@tcd.ie>

Kind regards, Sarah