Changeset: 57922756
work on duplicate segment
Closed by EdSS
Tags
changesets_count | 12003 |
---|---|
created_by | iD 2.7.1 |
host | https://www.openstreetmap.org/edit |
imagery_used | Mapbox Satellite |
locale | en-US |
Discussion
-
Comment from Mashin
Hi EdSS,
Any reason for disconnecting these and all the other buildings?
This two buildings are physically attached without any passageway leading to the court. So far I see it as a candidate for revert. -
Comment from EdSS
Hi Mashin,
I am afraid I do not recognize the area you show but I have separated touching buildings that generate a duplicate segment fault because they share a touching outer relationship for one multipolygon object.
The only two ways I know to clear the fault are to separate the outer segments from contact or to combine the two outlines as one building.
I would be happy to hear other ideas. -
Comment from Mashin
What tool does report this as an error?
As far as I know it is common practice to draw buildings that are touching as areas that have overlapping line segments (and it doesn't matter if it is a simple area or a multipolygon). -
Comment from EdSS
The tool is the website 'tools.geofabrik.de' using 'OSM INSPECTOR'. The issue in the change is Branford College and Saybrook College both claim an outer relationship to Memorial Quadrangle. This is just wrong because where they touch it is not an outer at all. The slight gap between them makes the outer legitimate and IMHO shows where each ends making a better map. You are correct about touching buildings but this is two parts of the one Memorial Quadrangle multipolygon object.
-
Comment from Mashin
The whole structure of the two Colleges is called Memorial Quadrangle and hence the multipolygon was created to avoid double naming.
I searched different sources about whether two touching outer members are valid an not, but only I could find is that two outer members touching in two nodes is valid: https://wiki.openstreetmap.org/wiki/Relation:multipolygon/validityAnd inner members sharing a line segment is OK (touching inner rings): https://wiki.openstreetmap.org/wiki/Relation:multipolygon
I am a little confused why two outer segment could not do the same.
-
Comment from EdSS
I still don't see the touching line having an outer relationship to Memorial Quadrangle but you are evidently the one with local knowledge. My only interest is to reduce the number of errors in the map and one error more or less is not earthshaking. If you are convinced that reconnecting the members would make a better map you can do it with no worries of an edit battle from me.
-
Comment from Mashin
From my point of view, since the two buildings are physically attached without any air gap, we should have them attached here as well, because we are mapping the reality.
What I agree is controversial is the Quadrangle multipolygon and its validity.
The Quadrangle (https://en.wikipedia.org/wiki/Memorial_Quadrangle) is the whole structure including all the courts and so 1) I could draw a new area around everything and name it Memorial Quadrangle or 2) create multipolygon relation and unite all the areas under one name. (Only the 'outer' role make sense, because 'inner' would exclude them.)Maybe I'll try to ask at OSM forum if anybody has a suggestion how to handle such cases.
Ways (3)
Nodes (5)
Welcome to OpenStreetMap!
OpenStreetMap is a map of the world, created by people like you and free to use under an open license.
Hosting is supported by Fastly, OSMF corporate members, and other partners.
https://openstreetmap.org/copyright | https://openstreetmap.org |
Copyright OpenStreetMap and contributors, under an open license |