Interesting that these maps are always binary: light or dark, when the intensity of light varies based on how high the sun is in the sky. Is there a version of this map that takes that into account?
Human vision has two logarithmic-response mechanisms in a row: the expanding/contracting iris, and the rods/cones (and many other nerve cells') logarithmic response.
Meaning: you get full visual acuity with just a little light. Further increases often don't even register.
In numbers: typical overcast daylight is around 1,000 lux. Full sunlight is above 100,000 lux.
I'm thinking more of an Irradiance map where the value is the current W/m^2 at a specific location, which would take into account latitude and time of year (to get the angle of the Earth relative to the sun), along with other factors like clouds, altitude.
As a start, it will be nice to just show the relative intensity of the light ignoring clouds and stuffs ... for example, people should know early morning, mid day and evening from the map which helps which part of the globe is going to get active/inactive
The page could be modified to present a gradient, since it only requires calculating the sun's altitude and solar time, which is not that complicated.
[1] https://en.wikipedia.org/wiki/Twilight