Show mouseover pixel value

[cpvargas]

Currently the mouseover shows the coordinates with 5 decimal points i.e. ( 200.12345 , -20.12345 ) it would be nice to add the value of the pixel that you are pointing at, e.g. to check the amplitude at the center of point sources

[JBorrow]

Unfortunately with the way the system is architected this isn't really possible.

[JBorrow]

After some discussion on Slack, we noted that it may be possible to implement an aperture photometry mode that calculates values within a fixed circular aperture. On layer change it would recalculate.

[msyriac]

If you plan on implementing aperture photometry, make sure it also does a quick background subtraction (i.e. (value in disk minus value in small annulus around disk)) as the raw values can be misleading in maps with a lot of CMB background. Perhaps that is already what you were planning, but commenting just in case.

[JBorrow]

Right now the plan is just to implement this so that we provide information on the actual data in the map. We aren't making any assumptions about the contents of the map. We will not call this aperture photometry because it's not really aperture photometry, just a way of extracting values from the map directly.

[msyriac]

Background subtraction is always a good idea regardless of the contents of the map. It is usually implicit when you say "aperture photometry", so esp. if astronomers use this, you may want to leave open the possibility of always doing it.

[JBorrow]

Ok! Thanks for your feedback.

[JBorrow]

#40 implements this, once frontend changes have been added we will merge and deploy.