Usage: 3dXYZcat [options] dataset dataset ...
* Catenates datasets spatially (for time cat-ing, cf. 3dTcat).
* The input datasets must match, in the sense that the pieces
  fit together properly (spatially and in time).
* Unlike in 3dZcat, all input datasets must be stored with the
  same data type (e.g., shorts, floats, ...); also, sub-brick scale
  factors are not allowed.  If you need to spatially catenate scaled
  short datasets, for example, convert them to float format using
  '3dcalc -float', then catenate THOSE datasets.

  -prefix pname = Use 'pname' for the output dataset prefix name.
                    [default prefix = 'xyzcat']
  -verb         = Print out some verbositiness as the program proceeds.
  -dir Q        = Catenate along direction 'Q', which is one of
                    X or Y or Z (synonyms are I or J or K)
                  which are the STORAGE directions (not DICOM) of the
                  3D grid of the input datasets.
                    [default direction = 'X', for no good reason]

Command line arguments after the above are taken as input datasets.

* If the i-th input dataset has dimensions nx[i] X ny[i] X nz[i], then
    case Q = X | I ==> all ny[i] and nz[i] must be the same;
                       the output dataset has nx = sum{ nx[i] }
    case Q = Y | J ==> all nx[i] and nz[i] must be the same;
                       the output dataset has ny = sum{ ny[i] }
    case Q = Z | K ==> all nx[i] and ny[i] must be the same;
                       the output dataset has nz = sum{ nz[i] }
* In all cases, the input datasets must have the same number of
  sub-bricks (time points) and the same data storage type.
* You can use the '3dinfo' program to see the orientation and
    grid size of a dataset, to help you decide how to glue your
    inputs together.
* There must be at least two datasets input (otherwise, the
    program doesn't make much sense, now does it?).
* This is mostly useful for making side-by-side pictures from
    multiple datasets, for edification and elucidation.
* If you have some other use for 3dXYZcat, let me know!

** Author: RW Cox [Dec 2010] **

++ Compile date = May 11 2021 {AFNI_21.1.07:linux_ubuntu_16_64}