I am looking for a free data feed (with HTTP(S) API) which I can use for various demos:
- something that I can map (both as markers and a heat-map)
- and chart the values
- real-time, and at least part of it should update often enough that someone looking at the page for 30 seconds (preferably less) will notice change
- UK based is "nice to have" (London only is also acceptable), I also like Singapore (where the government have a lot of open data), but will accept anywhere
- a single datum suffices (with multiple values; e.g datum is train, values are all trains, multiple datums (data) would be different train companies)
Any ideas?