Image DM changes suggestions and questions

[Louys Mireille]

Daer Doug, mark , DM WG members,

Here are a few more suggestion for changes or precisions to ImageDM:

Dataset.Image.Nsubarrays
Dataset.Image.Naxes
Dataset.Image.Naxis
These are dimensions specific for Image, cubes , sparse cubes :
I would prefer Dataset.Dimensions to replace prefix: Dataset.Image ;this 
is more general.

We know we are dealing with Image instance because:
Dataset.dataproductType='image' and we refer to DataModel.name='ImageDM'

Provenance :
more preferable to use ObsCore Utypes , because they reflect better 
possible extensions
on the Instrument and Facility class.
Up to know Obscore has an embryonic part of ObsConfig that can be 
re-usedand developped further .
Provenance.ObsConfig.Bandpass   not clear what to do ?
Provenance.ObsConfig.DataSource  more explanation needed

Complete ImageDM Items with ObsCore fields :
refval but also min and max values if defined in Obscore . Could be 
defined in ImageDM but optional .

Data.Naxes
Data.Naxis
isn't it redundant with  Dataset.Image.Naxes, Dataset.Image.Naxis ?
Are these the particular sizes of each chunk of data?
Then Dataset.Image.Naxes and Dataset.Image.Naxis could be the overall
  size of the combination in case of complex , or assembled data chunks.
Is it clearly defined in Image DM?

Any comments on this?
thanks , Mireille