Thank Bruce,

sorry for my simple question. I try to display one subject's thickness map on average surface. so I try

mri_surf2surf --srcsubject /root/freesurfer/subjects/r00275571 --srcsurfval /root/freesurfer/subjects/r00275571/surf/lh.thickness --trgsubject /root/freesurfer/subjects/fsaverage --trgsurfval /root/freesurfer/subjects/fsaverage/surf/mylh.thickness --hemi lh  

but i get error message: ERROR: could not determine type of /root/freesurfer/subjects/fsaverage/surf/mytlh.thickness

how can I correct it ? thank in advance

best

JLH