Platform and Platform edge duplication

[detective-fiasco]

For railway=platform_edge tagged also as public_transport=platform (which is usually necessary to add these platform edges to PTv2 route relations as a platform member) ORM-vector shows two objects: A platform edge and also a platform.

I would propose to render public_transport=platform as platform only if there is not a railway=platform_edge tag present on that same object.

Example could be this platform edge: https://www.openstreetmap.org/way/172978242

public_transport=platform
railway=platform_edge
ref=6
train=yes

bench=yes
covered=yes

Visualized here:
https://openrailwaymap.app/#view=20/49.9572366/14.076919

[Anasmasuris]

Why it's necessary to add public_transport=platform to railway=platform_edge in the first case? I haven't stumbled upon that case (in PL, DE, FR and other countries). The platform member in that case isn't the relation/area consisting of railway=platform?

[detective-fiasco]

You're right that this could be avoided by using the railway=platform relation as the platform member of the PTv2 route relation.

Isn't it better to use the platform_edge if it's present, though? I would argue it adds more detail, although it doesn't strictly follow the specification. Generally, when someone uses the platform_edge as the the platform route member (even for example with public_transport=platform_edge tag), it gets flagged by a PTv2 validator (which is technically correct) and it is often replaced or amended with the public_transport=platform tag within a few days by other users.

In either case this problem is not limited to platform_edges in Czechia (it seems to be mostly limited to Europe though); see https://overpass-turbo.eu/s/2nOf

[hiddewie]

Given the documentation on https://wiki.openstreetmap.org/wiki/Tag:railway=platform_edge and https://wiki.openstreetmap.org/wiki/Tag:railway%3Dplatform, tagging the edge of a platform with railway=platform does not seem useful nor correct. If such tagging is done to correct validation errors for relation members, then either the validation should be fixed, or the relations should be modified.

I would propose to render public_transport=platform as platform only if there is not a railway=platform_edge tag present on that same object.

Theoretically we could do this. But it would be working around the incorrect tagging instead of fixing the tagging. For example https://www.openstreetmap.org/way/684142022.

Instead, I would consider this situation for outputting a warning in a diagnostics layer (see #648, not implemented yet).

[detective-fiasco]

@hiddewie ...tagging the edge of a platform with railway=platform does not seem useful nor correct

The platform edges in question are tagged with railway=platform_edge and at the same time with public_transport=platform.

I do agree that tagging a platform edge with railway=platform is incorrect, since a better accepted alternative exists (e.g. railway=platfrom_edge), but that's not exactly the case with the public_transport key.

Putting this in the diagnostics layer would be nice though.

[hiddewie]

Ah sorry I missed that it was the public_transport key, not the railway key. Yes then the issue makes a lot more sense to not import platform edges as platforms. Then I also understand why mappers tag the edges as public transport platform and include those in the relation, which sounds sensible.

[hiddewie]

This will be fixed with #905