# 3dTagalign¶

```
Usage: 3dTagalign [options] dset
Rotates/translates dataset 'dset' to be aligned with the master,
using the tagsets embedded in their .HEAD files.
Options:
-master mset = Use dataset 'mset' as the master dataset
[this is a nonoptional option]
-tagset tfile = Use the tagset in the .tag file instead of dset.
-nokeeptags = Don't put transformed locations of dset's tags
into the output dataset [default = keep tags]
-matvec mfile = Write the matrix+vector of the transformation to
file 'mfile'. This can be used as input to the
'-matvec_in2out' option of 3dWarp, if you want
to align other datasets in the same way (e.g.,
functional datasets).
-rotate = Compute the best transformation as a rotation + shift.
This is the default.
-affine = Compute the best transformation as a general affine
map rather than just a rotation + shift. In all
cases, the transformation from input to output
coordinates is of the form
[out] = [R] [in] + [V]
where [R] is a 3x3 matrix and [V] is a 3-vector.
By default, [R] is computed as a proper (det=1)
rotation matrix (3 parameters). The '-affine'
option says to fit [R] as a general matrix
(9 parameters).
N.B.: An affine transformation can rotate, rescale, and
shear the volume. Be sure to look at the dataset
before and after to make sure things are OK.
-rotscl = Compute transformation as a rotation times an isotropic
scaling; that is, [R] is an orthogonal matrix times
a scalar.
N.B.: '-affine' and '-rotscl' do unweighted least squares.
-prefix pp = Use 'pp' as the prefix for the output dataset.
[default = 'tagalign']
-verb = Print progress reports
-dummy = Don't actually rotate the dataset, just compute
the transformation matrix and vector. If
'-matvec' is used, the mfile will be written.
-linear }
-cubic } = Chooses spatial interpolation method.
-NN } = [default = cubic]
-quintic }
Nota Bene:
* The transformation is carried out
using the same methods as program 3dWarp.
Author: RWCox - 16 Jul 2000, etc.
++ Compile date = Jan 21 2021 {AFNI_21.0.05:linux_ubuntu_16_64}
```