Example:
vgetcontrast -in beta.v -con 0 0 1 0 -1 0 0 -out cmap.v -type conimg
This call produces a contrast image from a beta map using the contrast vector 0 0 1 0 -1 0 0.
The length of the contrast vector must agree with the design file dimension, i.e., the length of the contrast vector must coincide with the number of covariates (number of columns ins the design matrix). The right number of covariates can be obtained using the program 'vcheckdesign'.