[daip] Scaling problem for model in VPLOT

[Eric Greisen]

Craig Walker wrote:
> We were running UVFIT which leaves a CC table attached to the UV data 
> set.  We then tried to plot the data and model using VPLOT.  That works, 
> but there is clearly a scaling problem of some sort with the model.  The 
> model line shows phase winds at an extremely high rate (seconds) when it 
> should have a turn or two across the day.  We then copied the CC table 
> to an image that had been made from that data set and re-ran VPLOT, 
> pointing to the CC table now attached to the image (exactly the same CC 
> table that was attached to the UV data set).  Now the plot comes out fine.
> 
> A probably-related problem occurs with PRTCC.  When printing the CC 
> table from UVFIT when it is attached to the image file (after TACOP), it 
> shows normally.  When printing it while attached to the UV data, the 
> positions are in units of kilo-arcsec and the position values all show 
> as 0.00.
> 
> I suspect that both PRTCC and VPLOT get some sort of scaling information 
> from the header that is not really available for a UV data set.  Somehow 
> this doesn't cause a crash, but does cause massive confusion about the 
> meaning of the position offsets.
> 
>
PRTCC used the image axes to set print scales (deg, arc sec, milli 
arcsec) and modeling software made deep assumptions that CCs are only on 
images.  I think I fixed it to the level that UVSUB seems to work as 
well as VPLOT and PRTCC.  Also fixed a phase flipping problem with plot 
scales not having been applied to the model plot.

Cheers,

Eric Greisen