This is because it takes two passes through the transform. One takes each target vertex and finds the closest source vertex. The other takes each source vertex not already sampled and finds the closest target vertex to make sure that every source is represented. With the 2nd step, there may be some target vertices that have multiple sources, in which case the values are averaged, which is why you see some fractional values. You can add the flag --mapmethod nnf and see if that fixes it. "nnf" mean nearest-neighbor-forward (1st step) whereas the default is "nnfr" (both steps) where the r means "reverse"
On 5/11/2021 7:25 AM, Mason Wells wrote:
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Hi experts,
I am trying to resample some surface overlays from fsaverage to fsaverage_sym surface. I have used the following command:
mri_surf2surf --srcsubjectfsaverage--srcsurfregfsaverage_sym.sphere.reg --trgsubjectfsaverage_sym--trgsurfregsphere.reg --hemilh--svallh.wang15_mplbl.mgz --tvallh.wang15_mplbl_fsaverage_sym.mgh
However, the data in the overlay has changed. The original overlay contains whole values, whereas the resampled overlay on _sym surface contains decimal numbers also. I wondered if you could advise me on whether the command I am using is appropriate?
Best wishes, Mason
*Mason T Wells, MSc*
*PhD student*
School of Optometry and Vision Sciences
& Cardiff University Brain Research
Imaging Centre (CUBRIC), School of Psychology
Cardiff University
Cardiff
CF24 4HQ
UK
*/Email/*: WellsMT1@cardiff.ac.uk mailto:WellsMT1@cardiff.ac.uk
*/Tel/*: 02920 879628
*Mason T Wells, MSc*
*Myfyriwr PhD*
Yr Ysgol Optometreg a Gwyddorau’r Golwg
& Canolfan Ymchwil Delweddu’r Ymennydd Prifysgol Caerdydd (CUBRIC), Yr Ysgol Seicoleg
Prifysgol Caerdydd
Heol Maindy
Caerdydd
CF24 4HQ
DU
*/E-bost/*: WellsMT1@caerdydd.ac.uk mailto:WellsMT1@caerdydd.ac.uk
*/Ffôn/*: 02920 879628
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