[Gnuplot-info] Having dual Celsius and Fahrenheit scales automatically?

[Alan C. <ala...@gm...>]

I can't find an example of where these are being set on the fly, and
for outdoor temperatures this is necessary since the ranges won't be
the same year-round.  After years of wishing I had a way to do this,
I've now got an Oregon Scientific temperature sensor outdoors with the
data being received by radio with an rtlsdr dongle, decoded by rtl_433
and formatted into something Gnuplot can plot by some C I wrote.  See
https://www.raspberrypi.org/forums/viewtopic.php?f=63&t=154451&p=1015069#p1015069

The thermometer setup gives me data in Celsius which I can plot fine,
but I'd like to add a Fahrenheit scale as Y2 at the right side.  Best
would be to have Y2 with its own tickmarks based on (Y1 * 1.8) + 32,
but it would be acceptable to have the same tickmarks with different
labels.  I can see how I could manually generate all the tickmarks and
labels within a program, but is there a way to do this in Gnuplot?
I'm aiming at having all this run by a cron job and generate a daily
plot.

I think normally I'd want to set y2range based on what yrange gets set
to automatically.  Or read the Y values at the tickmarks and calculate
new ones for Y2.  I don't want to plot more data, I just want to
calculate another set of tickmarks.  And it needs to change every day.


  Alan Corey
-- 
Credit is the root of all evil.  - AB1JX