usage: Convert a ROI graph to a volume, following labels and colors in a hierarchical nomenclature: values used in the volume will not be the index in the graph, but the "label" value in the nomenclature: thus the nomenclature has to have this attribute for each region, and be a number.
If no nomenclature is provided, regions numbers will be generated in an arbitrary order
The output volume will have a labels table with colors in the header attribute "GIFTI_labels_table", as in Gifti textures.
       [-h] [-i INPUT] [-n NOMENCLATURE] [-o OUTPUT] [-a ATTRIBUTE]

options:
  -h, --help            show this help message and exit
  -i INPUT, --input INPUT
                        input graph
  -n NOMENCLATURE, --nomenclature NOMENCLATURE
                        nomenclature (optional)
  -o OUTPUT, --output OUTPUT
                        output volume
  -a ATTRIBUTE, --attribute ATTRIBUTE
                        item attribute id (bucket attribute id in vertices).
                        Default: use the one available if only one is present