Characterization question

[Mireille Louys]

Hi Laszlo,

As Arnold already answered, you mention an example with two axes on  
spectral content, distinguished in SpectralAxis ( Ansgtrom) and  
RedShiftAxis (vel).
The Characterisation DM partly re-uses the STC definitions.
Characterisation v2.0 covers the description of RedShiftAxis (on progress).
I will be glad to work on an example of your metadata to check the mapping.
more below...

Laszlo Dobos <dobos at pha.jhu.edu> a écrit :

> Hi group,
>
>
>
> How do I specify overlapping axes in characterisation?
>
>
>
> Let's say I have a spectrum and want to give the spectral axis in both
> angstroms and velocities. Do I just add two axes and mark them both SPECTRAL
> and assume that they overlap?
>
>
>
> What if I have an image with two spatial axes? Do I add two SPATIAL axes
> then or just one and assume that the resolution etc. is the same in both RA
> and Dec?
>
>
CharDM considers the Spatial axis is 2D or 3D . As in STC, resolution  
will have the dimentionality of the Coordinate : 2D or 3D.
>
> What if I have overlapping spatial axes, let's say ra,dec and (for a not too
> good example) also Mpc? How do I associate one Mpc axis with Ra and the
> other with Dec.
>
CharDM V1 and 2 consider the same units on all spatial dimensions.
Interesting to consider your use-case.
>
>
> I'm sorry, if I misunderstood something about the whole thing. (Samples on
> the CDS server are unfortunately not available).
>
Sorry. Thanks for the feedback , will fix this.
>
>
> What I'm actually working on is a generic toolkit to characterize data cubes
> with any number of dimensions, and I want to allow using multiple scales
> along the axes.
>
Great! What about circulating an example of your metadata so that we  
could check how it fits to what we have in existing data models and  
what can evolve.

Many thanks, Mireille.