Talk:Speed limits

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Source:maxspeed or maxspeed:type?

We have a long running dispute or confusion on whether to put the type of speed limit using the county code format in maxspeed=*, using source:maxspeed=* or using maxspeed:type=*. To make it easier to talk about this I have reduced both source:maxspeed or maxspeed:type to short summaries with links to this article. Lets discuss the issue here. PeterIto (talk) 01:31, 24 February 2013 (UTC)

Preference for using source:maxspeed to hold the legal form of the speed limit

The following discssion has been moved here from talk:key:source:maxspeed

I appreciate your effort to restructure the wiki and think that the speed limit overview page is a good thing. Still I'd prefer to keep a pure, extensive definition of the source:maxspeed-tag here on the key-page (the overview could then link here). I'd also prefer to have it unambiguously describing what it described for the past years (instead of the new wording: some use it for A some for B), and to have the note about people using this tag to map the source they took the data from (like the actual values survey, massgis, etc.) as note at the end, with a discouraging phrase to not use it this way, and probably with an alternative suggestion how the survey-source could be mapped (e.g. maxspeed:source, or in a changeset comment, or ...). In general my approach would be to try to persuade those mapping not in accordance with the wiki definition to change their tags instead of documenting all kind of diverging uses to in the end have no direction any more for anybody.

I do agree that rival tags are not desirable, that's why I'd discourage the use of maxspeed:type ;-) --Dieterdreist (talk) 17:31, 20 March 2013 (UTC)

I understand that you a confident that source:maxspeed is the correct tag for holding information about the type of the speed limit (numeric etc), however there are a significant group who believe this should be used to indicate how the information was gathered and who advocate the use of maxspeed:type. As evidence for this I note that taginfo for this tag shows that the 3rd, 7th and 10th most common uses of this tag are to indicate where the data originated from. Personally, I see the argument for maxspeed:type, however I am taking the position of encouraging the community to come to an agreement on this, and prior to that happening, I do suggest that it is appropriate to flag up the dispute and create a single place to hold the debate. As I have noted above, I suggest we do that on talk:Speed limits. I have created a topic headed ' Source:maxspeed or maxspeed:type? ' for that purpose. If we can't agree then I suggest it is one for the talk_tagging list. Are you Ok with that? PeterIto (talk) 10:26, 21 March 2013 (UTC)
I propose to move this discussion to talk:Speed limits to keep the debate together in one place. I will do so in a day or two unless there are objections. PeterIto (talk) 05:59, 22 March 2013 (UTC)
A few observations:
  • The purpose of source:maxspeed was clearly documented, and the tag is already quite widely used for the intended purpose.
  • There was no preceding discussion about changing the meaning of source:maxspeed.
  • The use of maxspeed:type is sharply limited to Britain:
  • The 3rd most common use of source:maxspeed does indeed match the different interpretation of the key, but its value clearly indicates an import rather than human mapping.
In my opinion, this is not a situation that could be described as two interpretations carrying equal weight. I see one good argument for the migration of the old definition of source:maxspeed for maxspeed:type, which is that it is more consistent to always use source:* for the same purpose as Key:source. However, I'm not convinced that this justifies years of uncertainty about correct tagging practice, and the invalidation of existing mapping which was fully supported by the wiki documentation.
I can think of two resolutions of this situation:
  • Deciding that maxspeed:type is indeed the nicer tag because of consistency, and gaining community consensus to run a bot to migrate all uses of source:maxspeed matching the old definition to maxspeed:type.
  • Alternatively, reverting Key:source:maxspeed back to its original definition.
--Tordanik 08:53, 27 March 2013 (UTC)
Thanks for your very helpful comments. I agree that the objective should be to gain consistency on this. The one observation I would make in response to your binary proposal is related to your second choice... If we do revert to source:maxspeed then where should people put any 'source' information of the traditional sort? Personally I think it is particularly important with speed limit data to know when the tag value was last validated. PeterIto (talk) 09:46, 27 March 2013 (UTC)
Well, that's why I would actually prefer the first solution. But as for #2, there is still the option to apply changeset source tags when updating maxspeeds, which is the style I personally use anyway. --Tordanik 20:58, 27 March 2013 (UTC)
Agreed. That is my position as well. In response to your second suggestion, that begs the question as to what tag one should use in the changeset - do you use a simple source tag, ie 'source=Blar council speed limit database - Nov12' or what? I certainly wouldn't encourage tagging where it is impossible to tag detailed source information in the feature itself. PeterIto (talk) 06:46, 28 March 2013 (UTC)

Updates to the above discussion?

Has there been any updates to the above discussion? I'm about to start editing maps in and around the Glasgow area, including a large portion of rural roads, which contain Nation Speed Limit Signs, both single and dual carriageways. Before I start, what is the correct tag to use? Thanks! --Nickweb (talk) 22:18, 23 February 2015 (UTC)

Map what you see

My initial improvement suggestion was to tag streets without signposted speedlimits with implicit values like maxspeed=rural/urban/motorway/nsl_single/nsl_dual. Later we decided that it might be a good idea to prefix it with a country-code as the values have different meanings in different countries. But than some users strongly objected against any non-numeric values in maxspeed. As a compromise the non-numeric values have been moved to maxspeed:source which later have been renamed to source:maxspeed=*. This is somewhat problematic, because source:* tags have always been used for free-text description on how the tag has been obtained. zone:maxspeed=* (and zone:traffic=*) have been invented to circumvent this problem. At some point British people invented maxspeed:type which seems to be identical to zone:maxspeed.
Since then the community accepted several non-numeric values for maxspeed and we should rethink about putting implicit things we see on traffic-signs into the maxspeed-tag.
Nevertheless there is to much redundancy between maxspeed:type, source:maxspeed and zone:maxspeed! Perhaps we should accept the British-tag and rename source:maxspeed to maxspeed:type.
My suggestion is to only tag explicit values where you can see them sign-posted! The interpretation of implicit values can and should be done by software.
--phobie m d 13:22, 14 May 2014 (UTC)

In the UK the tag maxspeed:type=* is often used now for storing this info, so that the source variant can be used for survey, sign, import or whatever. Smsm1 (talk) 11:07, 20 May 2014 (UTC)
I agree. I have always preferred implicit values (e.g. maxspeed=DE:urban) as this is easier to map and less error-prone. Redundancy is generally bad in databases. The only reason to use a separate tag source:maxspeed was that routing app developers were too lazy to implement recognition of implizit values. Now millions of mappers need to tag billions of roads twice for the benefit that two or three developpers don't need to add a couple of source code lines and a table, which would take 5 minutes of work.
That said, explicit maxspeed values are preferred by most mappers, and I have no desire to start edit wars with them. I recently switched from source:maxspeed to maxspeed:type though, as this seems more sensible. I like the idea of changing all existing source:maxspeed to maxspeed:type. (Of course, we should only change tags with value patterns looking like zones. Tags like source:maxspeed=survey need to be left untouched.) --Fkv (talk) 14:37, 17 September 2014 (UTC)