# -*- coding: utf-8 -*-

"""

.. _ex-virtual-evoked:

=======================

Remap MEG channel types

=======================

In this example, MEG data are remapped from one channel type to another.

This is useful to:

- visualize combined magnetometers and gradiometers as magnetometers

or gradiometers.

- run statistics from both magnetometers and gradiometers while

working with a single type of channels.

"""

# Author: Mainak Jas <mainak.jas@telecom-paristech.fr>

# License: BSD-3-Clause

# %%

import mne

from mne.datasets import sample

print(__doc__)

# read the evoked

data_path = sample.data_path()

meg_path = data_path / 'MEG' / 'sample'

fname = meg_path / 'sample_audvis-ave.fif'

evoked = mne.read_evokeds(fname, condition='Left Auditory', baseline=(None, 0))

# %%

# First, let's call remap gradiometers to magnometers, and plot

# the original and remapped topomaps of the magnetometers.

# go from grad + mag to mag and plot original mag

virt_evoked = evoked.as_type('mag')

evoked.plot_topomap(ch_type='mag', title='mag (original)', time_unit='s')

# %%

# plot interpolated grad + mag

virt_evoked.plot_topomap(ch_type='mag', time_unit='s',

title='mag (interpolated from mag + grad)')

# %%

# Now, we remap magnometers to gradiometers, and plot

# the original and remapped topomaps of the gradiometers

# go from grad + mag to grad and plot original grad

virt_evoked = evoked.as_type('grad')

evoked.plot_topomap(ch_type='grad', title='grad (original)', time_unit='s')

# %%

# plot interpolated grad + mag

virt_evoked.plot_topomap(ch_type='grad', time_unit='s',

title='grad (interpolated from mag + grad)')