I’m trying to resolve a “warning”: “Relation contains a gap” for relation r2992240 , I don’t see what this is at all which is wrong. For information, I am only seeking to correct, I am not the author of the cartography.
Thanks in advance.
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What is giving this warning?
Note that gaps in some relations are fully correct.
If you are unfamiliar with situation on the ground and you have no good sources to help, it is better to not edit.
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Thank you for your comment. This is reported by osmosis and also by josm validation.
Loading the relation into JOSM’s relation editor should show where the gap is.
PTNA provides an analysis for Strasbourg, but covers only CTS, but not “Fluo Grand Est”.
In cases of a gap, PTNA gives the name of one highway ending at the gap.
Edit: add image, showing gap
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Hello
Thank you for your answer ! That was the problem, indeed: there was an unconnected section, hardly visible on JOSM, but obvious on ID. I’ll try your method next time.
Best regards.
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Unfortunately your changes did not solve the issue but added more problems like overlapping highways.
Extending the highway to fill a gap is usually the wrong way. Instead adding the missing ways as members to the relation is usually the way to go.
Looking at https://www.openstreetmap.org/relation/2992240/history the problem here is that the relation looks like public_transport:version=1 instead. The tag was not set until you added public_transport:version=2. While version 2 should not contain any gap and be represented as a single connected line, it represents only one route in on direction of a line. Version 1 represents the complete line with all its variants in both directions and caused by its nature can often not be represented as a single connected line.
The validator warning about gaps is only triggered if all members of the relation are downloaded and if public_transport:version=2 is set.
If you want more distinct warnings about public transport relations in addition to more tools you might be interested in the plugin pt_assistent.
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Bonjour,
Thank you for these valuable tips. It’s clear !
The relation editor shows gaps if the route is linear, but if the route goes in loops, or coming back from a slight detour, the relation can be ok, even if there are “red icons”. In such cases you often have to check every way segment which is a part of the route. Very tiresome and boring.
I can only quote myself:
So any public_transport:version=2 should not contain any gap even with loops and detours. If a way is passed several times it should be as (duplicate) member to the relation the same amount of times.
It is a whole different story if we talk about public_transport:version=1. It is still possible to have a linear representation for both directions using the roles forward and backward for ways traveled only per one direction. As soon as there is a loop, detour or variants, you will find gaps. Some mappers cheat on detours adding duplicate members with different roles but that is not inline with the documentation.
I usually try to group the main variant for each direction without gap, if possible, and use as less additional branches as possible but I have to admit that the more different variants are included the more gaps exist and I am not aware of any QA tool which can handle it. So completeness can only be checked through visualization which in deed can be boring and cumbersome.