Feature request: Global Sun Elevation Isolines

torianus

The layer of Sun Elevation Isolines would help to interpret current temperatures in relation to the position of the sun in the sky.
In the link below I provide a picture with the example:
https://drive.google.com/file/d/1pf-VtOLIstrhQiZGxXO_c-VyFJQrKrF1/view?usp=sharing
The owner of the picture is www.jgiesen.de

Thanks for your attention.

idefix37

@torianus
At least an overlay (as option) showing the limit of night and day should be nice. As already requested by @MetallicPoison
https://community.windy.com/topic/6044/day-night-overlay

It would give an image looking to
https://www.star.nesdis.noaa.gov/GOES/GOES16_CONUS_Band.php?band=GEOCOLOR&length=48

Of course adding isolines of sun elevation would be even better.

torianus

@idefix37
There are some examples of real-time maps:
https://www.timeanddate.com/worldclock/sunearth.html?iso=20180706T1620
or
http://www.spacew.com/www/zenith.html

But I don't know what algorithms they use for drawing those contours.
I would use the Sun Position Algorithm and A General Algorithm For The Construction Of Contour Plots developed By NASA.
1.https://rredc.nrel.gov/solar/codesandalgorithms/spa/
2. http://www.pdas.com/conplot.html
Could be that some coordinate transformation applies to the result of the SPA algorithm before feeding it to the contour plotting.

Ciao guys

torianus

One more thing.
The equations in the SPA algorithm are of trigonometric nature, therefore it shouldn't be that hard to solve them when Elev.Angle=Const. Thus you get a contour function.Then after applying a coordinate transformation you end up with a compact mathematical function which subsequently can be expressed in the Javascript language.