I am trying to map subject-specific cortical thickness map to standard fsaverage space and I ran the following command where sub1_filled is my individual subject in native:

mri_surf2surf --srcsubject sub1_filled --srcsurfreg thickness --trgsubject fsaverage --trgsurfreg thickness --hemi lh --sval sub1/surf/lh.thickness --tval fsaverage/surf/lh.thickness

After I run the above command, I am getting the following output and error. I am not sure how to resolve this and whether there is something wrong with my command line or with the data. I would greatly appreciate any help.

Source registration surface changed to thickness

Target registration surface changed to thickness

7.4.1

setenv SUBJECTS_DIR /Users/sbajaj/FS_Projects/

cd /Users/sbajaj/FS_Projects

mri_surf2surf --srcsubject sub1_filled --srcsurfreg thickness --trgsubject fsav1 --trgsurfreg thickness --hemi lh --sval sub1/surf/lh.thickness --tval fsav1/surf/lh.thickness 

sysname  Darwin

hostname MDACM0CL9004107

machine  x86_64

user     sbajaj

srcsubject = sub1_filled

srcval     = sub1/surf/lh.thickness

srctype    = 

trgsubject = fsav1

trgval     = fsav1/surf/lh.thickness

trgtype    = 

srcsurfreg = thickness

trgsurfreg = thickness

srchemi    = lh

trghemi    = lh

frame      = 0

fwhm-in    = 0

fwhm-out   = 0

label-src  = (null)

label-trg  = (null)

OKToRevFaceOrder  = 1

UseDualHemi = 0

Reading source surface reg /Users/sbajaj/FS_Projects//sub1_filled/surf/lh.thickness

nquads=4456450,  nvertices=341

error: ERROR: MRISread: file '/Users/sbajaj/FS_Projects//sub1_filled/surf/lh.thickness' has many more faces than vertices!

Probably trying to use a scalar data file as a surface!