[Nexus] Correct way to specify multiple signals

[Peter.Chang at Diamond.ac.uk]

My suggestion would be an auxiliary attribute in the NXdata group to point to the dataset(s) to be optionally plotted alongside the signal dataset:

@signal: fitted
@auxiliary: [raw_data]

A default plot/display type would be handy as well as the plot dimensions to use:

@display: line
@display_dimensions: [-1] (last dim as default)

Or

@display: image
@display_dimensions: [-2,-1] (last two dims as default)

Regards,
 Peter


-----Original Message-----
From: NeXus [mailto:nexus-bounces at shadow.nd.rl.ac.uk] On Behalf Of Jacob.Filik at Diamond.ac.uk
Sent: 11 January 2018 13:34
To: nexus at shadow.nd.rl.ac.uk; nexus at nexusformat.org
Subject: Re: [Nexus] Correct way to specify multiple signals

Ah yes of course, I'm not sure we write that, we should.

(But it is one of the annoying attributes on the dataset, rather than the group, so you can only add it if you have control of what writes the HDF5 file, for externally linked data anyway).

Thanks.

Jake

-----Original Message-----
From: NeXus [mailto:nexus-bounces at shadow.nd.rl.ac.uk] On Behalf Of V. Armando Solé
Sent: 11 January 2018 13:16
To: nexus at nexusformat.org
Subject: Re: [Nexus] Correct way to specify multiple signals

On 11/01/2018 14:09, Jacob.Filik at Diamond.ac.uk wrote:

> This is really fun to try and do if energy can be the fast axis (for a dispersive detector) or the slow axes (for a monochromator scan) of the dataset.

The order of axes in NXdata should solve that.

Besides that, in the 2010 NIAC meeting it was decided to be able to associate an attribute"interpretation" to datasets with possible values "scalar", "spectrum", "image" precisely to know how to deal with multidimensional datasets assuming C order.

A 1000 x 2000 x 4000 dataset with attribute interpretation set to image would correspond to 1000 images of 2000 rows and 4000 columns.
A 1000 x 2000 x 4000 dataset with attribute interpretation set to spectrum would correspond to 1000 x 2000 spectra of 4000 channels.

At the ESRF we are using that since long ago and it is used to reduce user interaction and to present default views for individual datasets not selected via an NXdata group.

Armando

_______________________________________________
NeXus mailing list
NeXus at nexusformat.org
http://lists.nexusformat.org/mailman/listinfo/nexus

-- 
This e-mail and any attachments may contain confidential, copyright and or privileged material, and are for the use of the intended addressee only. If you are not the intended addressee or an authorised recipient of the addressee please notify us of receipt by returning the e-mail and do not use, copy, retain, distribute or disclose the information in or attached to the e-mail.
Any opinions expressed within this e-mail are those of the individual and not necessarily of Diamond Light Source Ltd. 
Diamond Light Source Ltd. cannot guarantee that this e-mail or any attachments are free from viruses and we cannot accept liability for any damage which you may sustain as a result of software viruses which may be transmitted in or with the message.
Diamond Light Source Limited (company no. 4375679). Registered in England and Wales with its registered office at Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, United Kingdom


_______________________________________________
NeXus mailing list
NeXus at nexusformat.org
http://lists.nexusformat.org/mailman/listinfo/nexus