Pins come from logged gigs
A concert map should mark rooms you were in. If you did not attend, the city does not get a pin because a tour poster mentioned it. Radar places pins from your diary: venue and city on each gig.
That is why messy venue names matter. “Academy” with no city collapses nights that were hours apart.
Cities versus venues
City totals answer “where do I go”. Venue totals answer “which rooms”. Both are useful. A map that only shows counties hides the difference between a club and an arena in the same postcode.
Pro includes the map of venues you have visited. The underlying list is still the diary, which you can read without the map.
Festivals need a real place
A festival in a field still has a site. Log the festival name and the place it happened, or the pin sits on the wrong town. Day tickets at the same site can share a place without becoming twenty fake venues.
Correct a wrong city when you notice it. One bad pin makes the map look like you toured a country you drove past.