When I evaluate
CityData[All, "Coordinates"]
Mathematica returns
{Missing["NotAvailable"], Missing["NotAvailable"]}
but when I evaluate CityData[All]
or CityData[{All, "USA"}]
, it behaves as expected, and returns a gigantic list of cities.
I'm curious to modify the neat example for FindShortestTour
, to use coordinates from CityData
-- yes it may take a very long time, but I'm curious to see for myself :)
My guess is that it is because not every city in the database has coordinates mapped thereto - but why is Mathematica failing this way? How can I programmatically eliminate the cities with 'bad' coordinates? Or programmatically build a list of all cities that do have coordinates?