[Freesurfer] questions about mapping volume data to brain surface and extracting cortical thickness

Hi FS experts: I have two questions about FS. (1) Is there a way that can map volume data(.hdr and .img file) to brain surface in FS? (2) I find a way that can extract cortical thickness automatically,first,the statistical significant areas derived from group analysis on qdec are converted to annotation file using mri_surfcluster,then i use mri_annotation2label to convert the annotation file to label file,finally, mri_label2label and mri_anatomical_stats are used to map the label file to each subject and obtain cortical thickness. I want to know if the process is correct.

any help appreciated