Feature request: colourbar with numerical scale

[bmiszalski]

Hi all,
A feature that would be really useful would be the ability to show a colorbar and scale (even if min/max values) like e.g.
https://matplotlib.org/stable/api/_as_gen/matplotlib.pyplot.colorbar.html

Some example usage would be to plot velocity maps on top of galaxies, where the maps are the outputs of IFU surveys. The colourbar would show the min/max velocities.
It would be nice if it could make use of BUNIT in the FITS header if possible (e.g. to display the units somewhere).

Please see attached images and html.
This uses some SAMI DR3 data and the fits2hips service to create an overlay that is adjustable via a transparency slider.
The code is a little old now (uses Aladin Lite v2), but should be functional.

HTML source for an example and screenshots available here: https://cloud.datacentral.org.au/s/Hc0zbCdu8tmDABd

Best regards,
Brent.

[bmiszalski]

I've also added some Python code to the above link.

[bmiszalski]

This is a mock up of what it might look like: