Time plots in topcat

[Mark Taylor]

Dear TDIG,

I take advantage of the virtual interop to mention[*] some
improvements I'm making in the handling of time data by topcat:
it's now easier to plot time series data.

[*] This is in the nature of a coffee-break conversation rather
    than a formal announcement

The Time Plot, which has been available for quite a while but has
until now been hidden in the Graphics menu, is now visible in the
main topcat toolbar alongside the other plot windows.
I have 'promoted' it in this way because it's now possible to
specify how you want the time coordinate to be interpreted,
which makes it more usable.
If the input VOTable has a TIMESYS element, it should be understood
(previous versions already did this).  But if the input table
has, e.g., time specified in JD or MJD or Decimal Year or ISO-8601,
you can now select this in the GUI (or in stilts using a parameter).
In previous versions you had to supply the value in seconds since
1970-01-01, which was both fiddly and non-obvious.

There are two differences between topcat's Time Plot and e.g.
the Plane Plot:

   - the horizontal axis is labelled as a time (ISO-8601, decimal year,
     MJD, Unix seconds)

   - you can stack multiple plots vertically with the same time axis
     (they scroll together)

An example screenshot is attached.

Note this is only in pre-release, so the documentation is not properly
in place and this functionality is subject to change.  But if anybody
wants to try it out feel free - any feedback is very welcome.
But if you prefer to leave the bleeding edge to others, you can
wait until it's in public release, when I will announce the
functionality and its documentation on the mailing lists
(http://www.star.bris.ac.uk/~mbt/topcat-lists.html).

Pre-release version here:

   ftp://andromeda.star.bris.ac.uk/pub/star/topcat/pre/topcat-full.jar

Thanks!

Mark

--
Mark Taylor   Astronomical Programmer   Physics, Bristol University, UK
m.b.taylor at bris.ac.uk +44-117-9288776  http://www.star.bris.ac.uk/~mbt/
-------------- next part --------------
A non-text attachment was scrubbed...
Name: TimePlotWindow.png
Type: image/png
Size: 47898 bytes
Desc: 
URL: <http://mail.ivoa.net/pipermail/voevent/attachments/20200504/1e134792/attachment-0001.png>