London Mashups OpenStreetMap

Ironways of London


It’s always irked me slightly that many online maps of London show the various tube services as straight lines between stations, or as idealised Bezier curves. Perhaps the regimented lines and angles of the official “Beck-style” tube diagram has meant that, when translating into a “real life” geographical map, people have tended to keep the simplifications. After all, if you are travelling around London on the tube or railways, only the location of the stations are important – not how you travel between them.

Focusing on the section of the DLR just south of Canary Wharf:

Google Public Transit view, using Bezier curves between stations:

A typical “straight lines between stations” map – from CASA’s own MapTube:

One of DLR’s own official diagrammatic maps:

Where the line actually goes:

OpenStreetMap contributors have faithfully mapped most of London’s railways, including best-guess alignments for tube tunnels, using ventilation shafts on the service and “feeling” corners and curves that tube trains take – bearing in mind that GPS does generally not work underground. There are a couple of minor mistakes, such as orientations of the Northern Line curves near Mornington Crescent, and a part of the Piccadilly Line in north London.

I’ve taken this now excellent dataset, and as part of work to produce a comprehensive vector file of Transport for London (TfL) service routes, I’ve produced this interim map – the Ironways of London. TfL’s public service routes are highlighted in green. Lines in red are other train operator routes, sidings and depots, freight rail routes, disused lines, unusual chords and the odd ornamental railway. Many of these are obscured by the green lines of TfL routes, where the two coincide. There are a few missing sections, e.g. a couple of tunnels to the south of London are not shown.

The map here uses Google aerial imagery as a background, Ordnance Survey Open Data to show the boundary of Greater London, and OpenStreetMap to show the rail routes themselves. As such, it’s a nice mashup of the three major sources of free-at-point-of-use spatial datasets for London.

Here is the full size version.

There are a few other examples around on the net of the same thing – here’s an ESRI one. The Carto Metro one is excellent and is a level of detail beyond what I am aiming for.

In the new year I hope to complete and release the tidied vector data. [Update: Data released, more info.]

5 replies on “Ironways of London”

Hello Oliver: re: “a couple of minor mistakes, such as orientations of the Northern Line curves near Mornington Crescent, and a part of the Piccadilly Line in north London” I would really like to get these fixed in OpenStreetMap. There’s a list of known errata back from around the time I was in contact with Richard Milton at CASA last year about the MapTube work. Would you be able to help improve the OSM dataset by listing any issues with the OSM Tube data that you’ve spotted?

Hi Paul

Most of the notes there are at for a much more detailed dataset/map than I need. The only two errors (compared with a “master”, non-open dataset from TfL) that I noticed when tracing the whole dataset into a simple fileset – see – is the western branch of the Northern line near Mornington Crescent – it actually goes along Hampstead Road. The other discrepancy was the Piccadilly Line between (I think) Bounds Green and Palmers Grove, where it follows the main road more closely than the OSM line suggests. All other errors were not large enough for my version of the map to be significantly affected.

Seems that the main problem with the google transit version is just that it accidentally misses out South Quay – if it didn’t then the Bezier curves would be a much better approximation!

What’s the grey line on the Google public transit view that follows the real north-south route accurately?

Yes (well above ground anyway) – but it’s grey, so not very useful for someone wanting to know what line it is. The dataset I’m building has the line names and colours coded into it.

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