Talk:Tag:surface=concrete:plates

Difference from surface:concrete - 2022-2023 discussion

What about plates which are not prefabricated, but cast in place with gaps between them - resulting in effectively the same surface? Mateusz Konieczny (talk) 18:37, 3 September 2022 (UTC)

IMHO, OSM users are not expert structural engineers (see Verifiability). If it walks and quacks like a duck, it is a duck. So if it looks and feels like concrete:plates, it is concrete:plates. --mnalis (talk) 20:05, 3 September 2022 (UTC)

Normal American sidewalk

I think what @Mateusz Konieczny: is describing here is identical to a standard American (and Canadian as far as I know) sidewalk (see the image on the right). It appears mappers are reluctant to use this, however, probably due to the connotation with "heavy duty": https://taginfo.geofabrik.de/north-america/us/tags/footway=sidewalk#combinations (~302 000 of surface=concrete vs ~18 000 of surface=concrete:plates in combination with footway=sidewalk in the US) At the very least, a sidewalk like the one shown here should be an example on the page, right? I'll also reach out to the US slack about this. --Popball (talk) 11:57, 10 September 2022 (UTC)

@Popball: that looks like surface=concrete to me Mateusz Konieczny (talk) 12:00, 10 September 2022 (UTC)

Shouldn't we change this definition ?

Proposal : Road made out of separate plates (cast on site or prefabricated). Can be distinguished from continuous cast lanes with transversal dilatation joints by the possible appearance of grass in the joints or differential movement between plates. Mostly found in rural areas and older roads/paths. For continuous concrete cast lanes with transversal joints, use surface=concrete. --Bruno1460 (talk) 15:24, 27 November 2023 (UTC)

@Bruno1460: (you forgot to sign so I added it) - we cannot really "change the definition". OSM wiki documents how tag is being used, so to change that, one would need to review all existing usages of the tag and evaluate/change that first. That is very hard (to say the least) to do when tag is already in widespread use. That is why making very clear and unambiguous tag description (of when tag is applicable and when it is not, preferably with examples for both categories) is of extreme importance -- however that can mostly be done only at tag creation time (i.e. before the tag gets wildly used). What can be done is to propose new tag(s) with much clearer definition, start using that, and when it is in wide use deprecate the old ambiguous tags in favor on new clear ones. However the benefit of doing that should be measured against the issues it invokes (e.g. not only effort needed, but also issues with tag proliferation ). --mnalis (talk) 18:30, 28 November 2023 (UTC)

I fully agree with you, but that principle prevents us from ever correcting an issue that might appear. About this specific tag, the current definition does not really correspond to its name, and that has lead to a lot of 'wrong' tagging. In particular, a lot of people have been tagging ways with surface=concrete:plates because these ways have transversal dilatation groves, thinking they are a sign of a construction with plates. The definition of surface=concrete specifically mentions that case and should be used. At the same time, many people do not dare ot use surface=concrete:plates when it is the case, because they look at the definition and are not sure if they are 'heavy duty'. In conclusion, we have a pretty wide array of usages for this tag, who has a very narrow definition. So my proposal is to widen the definition to make it more 'natural', correspond better to current use and specifically remove the conflict with the definition of 'surface=concrete. --Bruno1460 (talk) 04:03, 29 November 2023 (UTC)

Difference from surface:concrete - 2024 discussion

I would like to restart this discussion. I posted on the community forum about it: https://community.openstreetmap.org/t/surface-concrete-vs-concrete-plates/122298

The current wiki pages, including in different languages, are inconsistent about whether it’s important that the concrete is cast in place, or prefabricated, or undetermined. Expansion/contraction joints for surface=concrete are sometimes mentioned and sometimes not. (I collected the current wiki pages' text in the forum thread)

I would like to suggest the following changes:

• concrete to be used for concrete by default (except concrete:lanes which is about shape)
• concrete:plates to be used sparingly, only when mapper is quite certain that it is the right tag: that plates are prefabricated rather than cast-in-place, or when plates are visibly tied together with braces or ties
• where it is not clear whether it’s concrete:plates or concrete, default to concrete

My main reasoning and motivation is that an easily verifiable difference between concrete and concrete:plates has never been established, there is no clear and consistent guideline about when to use which tag, and mappers have been using concrete:plates for cast-in-place concrete sidewalks with minor control cuts (like the ones in the picture above) - some examples of this are in the forum thread.

I am aware that we can't "fix" the current tagging, but creating a much clearer definition, and getting help from apps like StreetComplete to use that definition, could help at least not add more mistakes. I would also keep a note in the wiki that some mappers have used the concrete:plates tag for “plain” concrete, to future data users.

Please feel free to comment on the forum or here.

--Jarek Piórkowski (talk) 14:22, 2 December 2024 (UTC)