Determination of station size

[Anasmasuris]

Hi, I'd like to ask what is the method of determination of station size for rendering station icon. In case of PL I can't exactly figure out, why the station with 3 platforms (and additional yard) is considered as "large", while stations with similar parameters or higher (being eg. 4 or more platforms) are considered as "small" or "normal". Examples:

• Łódź Widzew (3 platforms), large (https://openrailwaymap.fly.dev/#view=16/51.76347/19.544533&style=standard)
• Kraków Główny (5 platforms), normal (https://openrailwaymap.fly.dev/#view=16.5/50.068237/19.948351&style=standard)
• Ełk (3 platforms), small (https://openrailwaymap.fly.dev/#view=16.35/53.824296/22.363509&style=standard)
• Białystok (4 platforms), small (https://openrailwaymap.fly.dev/#view=17.03/53.133571/23.135071&style=standard)

Is it due to the quantity of tracks in given buffer or something else?

[wolfy1339]

It goes by route count

>= 20 routes = large
>= 8 normal
Else, small

It's all defined in import/sql/tile_views.sql
It was changed as part of #254

[hiddewie]

Yes exactly.

I plan to actually remove the label from the popup because it is not very useful and does not have an objective meaning at the moment. The heuristic values 8 and 20 are mostly chosen to have some number of stations be rendered at lower zoom levels, and with a suitable icon. The threshold values are rather arbitrary, and tweaked to make it look nice on as many zoom levels as possible, in as many countries as possible.

[hiddewie]

A bit more details:

The import imports:

• stations
• public transport stop_positions
• platforms
• public transport stop_area relations (only for nodes with platform or stop role)
• railway routes (for platform or stop relation roles)
  (this is in the import script https://github.com/hiddewie/OpenRailwayMap-vector/blob/master/import/openrailwaymap.lua)

Then after the import is the SQL script get_station_importance.sql which calculates the station importance:

• Stop positions are joined with the routes that contain the stop position
• Platforms are joined with the routes that contain the platforms
• Stop positions are "clustered" together within 400 meters if they have the same name
• Platforms are "clustered" together within 50 meters
• Stations are matched with stop positions if they are within 400 meters
• Stations are matched with the platforms if they are within 60 meters
• Finally everything is grouped together, such that stations end up with a single number that is the sum of the matched route count through platforms, and route count through stop positions.

[hiddewie]

I think I see the problem for Münster: for example platform 1 (https://www.openstreetmap.org/relation/5561455) is a relation, not a node or way. Platforms are only imported as node or way at the moment.

[hiddewie]

I think the second problem for Münster is that the station is named Münster (Westf) Hbf (short name) and Münster (Westfalen) Hauptbahnhof (name). The logic for joining stop positions with the stations is by name, and doing an exact match for stop position equal to station name. The stop positions are named Münster (Westf) Hbf (see e.g. https://www.openstreetmap.org/relation/1988251 and the stop/platform positions). So no matches are found.

[hiddewie]

Problem 1 (platform relations are not imported into OpenRailwayMap) can be solved easily. That will be done with #374.

Problem 2 is harder to solve. Ideally we could use the public_transport=stop_area relation (https://www.openstreetmap.org/relation/3058567) for that, but there are two problems with that:

• Not all stations have this relation tagged properly
• There are no roles documented for station (docs https://wiki.openstreetmap.org/wiki/Tag:public_transport%3Dstop_area). This would mean that post processing is needed to properly link stations, platforms and stop positions together. This is technically possible but work to implement properly.

[hiddewie]

Part 2 will be handled with #377.

If the public_transport=stop_area exists, it will be taken into account for finding platforms/stop positions of a station.

For Münster, that means 35 routes are found, from the previous 0 routes (before solving problem 1) and 5 routes (before solving problem 2).

That will make it a large station again 🎉