[superqwert]

I think I've found the issue with the 11m distance - the 11m distance is:

[-0.126102, 51.502769] to [-0.126018, 51.502714]

What is happening is that the TfL sequence API is starting the bus route sequence on one side of the road of Parliament Street, before turning it around at the corner with Whitehall Place. The bus stops on either side of the road are very close together. Other maps/sequences elsewhere start the sequence at the end of Parliament Street, meaning the short distance is avoided.

[zimpenfish]

Ah, you're parsing the `lineStrings` blob? I'm looking at the lat/long pairs in the `stopPointSequences` structure[1] which gives a different set of coords (in particular, 51.502769, -0.126102 doesn't exist as a stop for the 53.)

[1] `.stopPointSequences | .[0] | .stopPoint | .[] | [.name, .id, (.lat|tostring), (.lon|tostring)]` in jq parlance

[superqwert]

Interesting! I wonder why the Line strings blob differs... Maybe it doesn't represent bus stops at all, but points at which the route changes for the purpose of drawing?

[zimpenfish]

It does seem to be "the route as you'd show on a map" - if I plot the two sets points on GPSVisualizer, it's fairly different.

https://imgur.com/a/BUSW3C2

I guess the 389/631 routes are reasonably simple and don't need more "drawing points" than you'd get from the bus stops anyway?

[edit: added the 389 bus stops and line points to the imgur gallery]

[superqwert]

nice!

[superqwert]

In fact, it seems for 53 that none of the lineStrings match the stopPointSequence lat/lons

[superqwert]

but then... why would my query have matched your query in the cases of 389 and 631?!