gijzelaerr
commented
10 years ago Original comment thread migrated from bugzilla
at 2008-09-21 23:56:55 Oleg Smirnov replied:
When using the Collections Plotter for, e.g., residuals, it would be very nice to be able to plot IQUV in addittion to the four elements of the coherency matrix. These are easy to compute on-the-fly, and so should be relatively easy to implement.
Of course, this functionality should only be enabled if the input of the Collections Plotter is an ndim=[2,2] vellset.
The only thing that requires some thought is how to indicate this in the GUI consistently. The current right-click menu provides selection for the rather uninformative "vells 0", "vells 1", etc. Perhaps we can provide an optional keyword in the state record (a-la the "labels" array) which I can set to e.g. ["XX", "XY", "YX", "YY"] when building the tree, and the Collections Plotter can use these strings in the menu?
In fact, perhaps displaying of IQUV tracks should only be enabled if a special keyword is specified in the state record. It makes no sense when plotting Jones matrices, and would only confuse the user to have it in the menu then.
at 2008-09-22 05:12:37 Tony Willis replied:
You could add a 'vells_labels' record for the ["XX", "XY", "YX", "YY"] stuff and a 'stokes_labels' record for ["I","Q","U","V"]. I could add these options together so that the right context menu then offered the possibility of showing any possibility, e.g. XX or I
at 2008-09-22 15:12:07 Oleg Smirnov replied:
(In reply to comment #1)
You could add a 'vells_labels' record for the ["XX", "XY", "YX", "YY"] stuff and a 'stokes_labels' record for ["I","Q","U","V"]. I could add these options together so that the right context menu then offered the possibility of showing any possibility, e.g. XX or I
OK, excellent idea, that's exactly how we'll implement it. Please go ahead and modify the Collection Plotter accordingly.
BTW, it would be good if you supported an arbitrary (i.e. possibly shorter) stokes_labels list. Right now I'm only calibrating on XX/YY (due to strange signal in one of the cross-corrs), and my trees are built accordingly. I'll therefore create my collectors with stokes_labels=["I","Q"] only. This would keep the menus free of unnecessary clutter.
at 2008-11-06 21:07:39 Tony Willis replied:
We can surely do this a bit more elegantly, at least for the case of spigots and sinks. Somewhere in a MS header must be buried the info on whether the correlations are "XX", "XY", "YX", "YY" or "RR, "RL", "LR" and "LL". Couldn't this be passed to me as part of the cache record? I'm using calico-view-ms.py to look at some of the spigot output of my 3C84 data. I can see an obvious difference between the raw RR and LL data (RR decreasing when LL is increasing and vice versa) which shows the VLA squint behaviour. It would be nice to add the ability to get V from RR - LL.
at 2008-11-11 19:07:31 Tony Willis replied:
There is a sub-table POLARIZATION in a MS. It looks like XX XY YX YY correspond to polarization types 9, 10, 11 and 12 respectively while RR RL LR and LL correspond to types 5, 6, 7 and 8 respectively.
at 2008-11-11 19:58:15 Oleg Smirnov replied:
(In reply to comment #4)
There is a sub-table POLARIZATION in a MS. It looks like XX XY YX YY correspond to polarization types 9, 10, 11 and 12 respectively while RR RL LR and LL correspond to types 5, 6, 7 and 8 respectively.
Yep, I need to read that table anyway before I build Meow-based trees, because Meow needs to know the polarization type. At the moment linear is assumed (which BTW means I need to fix a few things before it will process VLA polarization correctly -- so could you upload a smallish VLA data set somewhere please?)
The rest should be taken care of by the vells_label field in the state record. You look at vells_label to figure out what correlations you have coming in, and from that you can compute IQUV accordingly. I'll take care of setting up vells_label correctly, based on the POLARIZATION table.
at 2008-11-25 16:36:40 Oleg Smirnov replied:
OK, since Jan has also requested more meaningful Vells labels in the result plotter, I'm thinking we need a simple general mechanism for passing this information around. This needs to be described/discussed in detail, so I've made a wiki page:
http://www.astron.nl/meqwiki/VellsLabelingScheme
at 2009-02-11 15:16:38 Oleg Smirnov replied:
* Bug 394 has been marked as a duplicate of this bug. *
at 2008-09-21 23:56:55 Oleg Smirnov reported:
Would be nice to plot IQUV in the Collections Plotter