[daip] Re: Stupid VLBI tricks #3

[Eric Greisen]

Robert B. Phillips writes:
 > 
 > 
 > 
 > 
 > Eric,
 > 
 > 
 > I have the following (understandable) problem:
 > 
 > 
 > 1) Two SiO data sets, nicely mapped to completion, but VLBI
 >    data from two different correlators, two bandwidths, two
 >    slightly different channel spacings (one .124km/s, other
 >    .109km/s, though that's not the problem);
 > 
 > 2) Data set #1 goes from 24 to 30 km/s, #2 from 20 to 32 km/s.
 >    Note range of #1 fits inside #2's.
 > 
 > 3) Want to display them side by side, same velocity palette,
 >    for making a nice figure for finished manuscript.
 > 
 > If you display these in nice TVHUE style letting TVHUE do its
 > thing with each, TVHUE expands the color transfer function and
 > wedge to reflect the range of the data set it currently is
 > handling.   Tried a colleague's suggestion to load data set #2
 > (one w/bigger velocity range), TVHUE it to my liking, then load
 > data set #1.   Didn't work (didn't think it would without extra
 > tricks).   Result was epoch #1 with its velocities scaled to
 > the color t.function last used.

    TVHUE just displays whatever's in the two channels.  Use PIXRANGE
when TVLOD loading the velocity channels.  It might be good also to
use a different PIXRANGE when loading the intensity channels so that
both would be on the scales.

 > 
 > What's the smart choice to display these two?   Use MCUBE to
 > round out data set #1 to 20 to 32 km/s ?    Or is there an
 > elegant way to talk to TVHUE & friends?
 > 
 > I got myself into this trouble by wanting to combine one of
 > the last (1998) Mark III dats sets with a real live VLBA one
 > from the month after.
 > 
 > Best wishes,
 > 
 > Bob P.
 > 
 > 
 > 
 > 
 >