Hi All,

I need to set the "center" field parameter for making a projection of the "radial_velocity".
I see from the docs how to do that for a data container but its not clear what to do for a
projection.

The error I am getting at the moment when the "center" is not set is:

File "/homeappl/home/regan/appl_taito/YT/Dev-3.0/yt/yt/data_objects/data_containers.py", line 249, in __getitem__
    self.get_data(f)
  File "/homeappl/home/regan/appl_taito/YT/Dev-3.0/yt/yt/data_objects/data_containers.py", line 656, in get_data
    finfo.check_available(self)
  File "/homeappl/home/regan/appl_taito/YT/Dev-3.0/yt/yt/fields/derived_field.py", line 146, in check_available
    validator(data)
  File "/homeappl/home/regan/appl_taito/YT/Dev-3.0/yt/yt/fields/derived_field.py", line 235, in __call__
    raise NeedsParameter(doesnt_have)
yt.fields.field_exceptions.NeedsParameter: (['center'])

Any tips much appreciated!


Cheers,
John