ylim in plot_evoked_topo

The ylim parameter in plot_evoked_topo is None by default and for this default, the channels have different ylim. I think this is a bad default because:

1. It does not allow comparison across channels (e.g., lateralization effects)
2. It does not allow you to easily spot bad channels

Instead, the ylim should be determined based on all the channels. One option is to copy the defaults from xplotter which are based on expected physical values of the quantities for evoked responses. The other option is to use the MAD or some such thing so that you get reasonable values even when bad channels are present.

[ramkpari]

Yeah , Definitely. For now , it looks like the defined ylims seems to be preserved while within plot_evoked_topo and somehow does some weird stuff after the data gets passed on to class _plot_topo , which is responsible for producing the actual plot.

Also looking back at the original issue, the default ylims being assigned when plot_evoked_topo is called with out any parameters seems to be in the magnitude of several hundreds. For evoked_meg in the above example, it’s specifically [(-548.98971293,548.98971293) , (-199.91518048,199.91518048).

[agramfort]

ok so presently you can zoom by drawing a square but the ylim is not adjusted dynamically

that seems something valuable to add !