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London Bus Stop Distance Analysis

michalpaszkiewicz.co.uk

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Re: London Bus Stop Distance Analysis

#11

Post by superqwert »

zimpenfish wrote: post #10
superqwert wrote: post #9

Earlier quoted context omitted.

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 s…

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

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?

Re: London Bus Stop Distance Analysis

#12

Post by superqwert »

zimpenfish wrote: post #10
superqwert wrote: post #9

Earlier quoted context omitted.

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 s…

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

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

Re: London Bus Stop Distance Analysis

#13

Post by superqwert »

zimpenfish wrote: post #10
superqwert wrote: post #9

Earlier quoted context omitted.

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 s…

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

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

Re: London Bus Stop Distance Analysis

#14

Post by zimpenfish »

superqwert wrote: post #11
zimpenfish wrote: post #10

Earlier quoted context omitted.

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

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?

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]

Re: London Bus Stop Distance Analysis

#15

Post by superqwert »

zimpenfish wrote: post #14
superqwert wrote: post #11

Earlier quoted context omitted.

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?

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]

nice!

Re: London Bus Stop Distance Analysis

#16

Post by zimpenfish »

simplesleeper wrote: post #4
zimpenfish wrote: post #3

Needs a discussion of the methodology of calculation. The distances I'm getting from the downloaded "bus-sequences.csv" (from TfL's API site) differ substantially; e.g my 53 has averages of 317m and 357m vs his 201m and 219m. Additionally, my numbers match up with those of 'superqwert from https://news.ycombinator.com/item?id=20029476 for the 389 and 631 routes. (I measured a bunch of stops of the 78 route with GPS e…

I think he is using bird's-eye view distances, as opposed to bus travel distances. Roads are rarely directly straight between stops in London

Seems to be a confusion over the data from the API - it returns a `lineStrings` array of GPS coords but those aren't the stops; it's the "plot these to visualise the route as it goes on the road". The actual bus stops are further down in a different structure.

Re: London Bus Stop Distance Analysis

#18

Post by JadeNB »

Schmazo wrote: post #17

Some people who you might not normally expect to, do concern themselves about bus routes. https://www.sidis.net/TransfersContents.htm

Does this person have some reputation that others of us could recognise, that would lead us to expect him not to be interested in bus routes? I found the site mystifying, but clicking around suggested someone more on the Timecube than the eminent-public-figure side.

Re: London Bus Stop Distance Analysis

#19

Post by mattlondon »

I wish we had more "long distance" buses in London.

It takes forever to get anywhere on a bus because it stops so frequently. I'd be really keen to get buses that dont stop until they get to major places.

E.g. you could have bus routes that only go between stations on different routes. Take Camden Town to Finsbury Park as an example - no direct rail route between them, about 2.5 miles apart by road. The 253 stops sixteen times (according to Google Maps) when going between those stations.

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