Why it sweeps west to east
The needle runs by longitude, so a drag crosses continents the way the sun
does and a country arrives as a run of stations rather than scattered
entries in a list.
Within the same longitude the busier station comes first,
so a sweep across a city lands on what most people are listening to.
Why some are missing
Only stations that stream over an encrypted connection are on the dial. A
page served over https cannot play an unencrypted stream — the browser
blocks it silently — so including them would mean a third of the
needle playing nothing.
The count of what was left out is shown when the dial
loads.
Why some do not play
These are volunteer-listed addresses and a fair share are dead at any
moment. A station that will not start says so and offers the next one along
rather than sitting silent.
Positions are where somebody said the transmitter is,
often the studio and sometimes a country’s centre point.