Formatting of prow_ref

Hi all,

@DaveF has commented on one of my changesets about the formatting of “prow_ref” on a public right of way. I think rather than a back and forth on that changeset it would be useful to get community input (again).

I had edited a right of way and, when doing so, I also made an edit to the prow_ref field.

PRoW refs are not consistent across different local authorities and sometimes are not even consistent within the same local authority (sometimes parish borders get changed etc). Cornwall’s referencing system for PRoWs is also on the more opaque end of things. For example, references show up on their PRoW map as “Parish/path no./link no. : 216/21/2”.

I therefore edited the prow_ref to fit a consistent format, matching a lot of other PRoWs in Cornwall (though, admittedly, I mapped a lot of them) and matching the suggestion on the wiki (</parish name/> </PRoW type/> </reference number/>) which follows on from discussions on talk-GB. Conveniently, this format is also consistent with @Robert_Whittaker 's PRoW progress tracker which allows PRoW mapping to be tracked, including in Cornwall. I also kept the original reference number on the way by adding prow_ref:official=216/21/2.

I feel that this is a sensible compromise. In doing so, we have a consistent tagging scheme of prow_refs across (large parts of) the country, in a human readable format, but can also add the authority’s formatted version if we want.

Dave contends that we shouldn’t be making up our own refs and that we wouldn’t do that on roads.

I disagree with this stance. Firstly, “prow_ref” is objectively an OSM object. I don’t think any local authority has a “prow_ref” field in their data. So it seems to me that it’s OK for us to format a local authority’s number to fit with a consistent formatting. Although the reference might not match the definitive statement, we aren’t making up our own ordering and so it is straightforward to understand the relationship if you have a look up table.

Secondly, UK road refs are a perfect example of a consistent formatting. How roads are referenced doesn’t change between local authority borders. Roads are also signed with their reference numbers on the ground. Public rights of way do not have consistent formatting for their refs and are not usually signed with a reference number. So, whilst tempting to make the comparison, I don’t think it quite holds.

So rather than the two of us arguing about this, I wonder if there is any community consensus :sweat_smile:

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The linked PRoW progress tracker links to a wiki page that says this:

Adding Official Reference Numbers

County Councils and Unitary Authorities have a duty to record Public Rights of Way in an official document called the Definitive Map and Statement. To do this, each Right of Way is given a unique name/number within the authority area. Usually the Rights of Way are numbered by civil parish, with names of the form “Springfield Footpath no. 3” etc. These names/numbers can be recorded in OSM using the prow_ref=* tag. For consistency in formatting, I would recommend adopting the common format “[Parish Name] [Type Code] [Number]”, where [Type Code] is either FP (public footpath), BR (public bridleway), RB (restricted byway), or BY (byway open to all traffic); unless the Surveying Authority has it’s own consistent numbering format/system.

(Emphasis added).

As you have described Cornwall as using a consistent format of “Parish/path no/link no” I don’t really see the benefit of re-numbering to be inconsistent with the official source. Of the suggest things to encode the only one not captured in Cornwall’s system is the [Type Code] from the generic system and that sounds like a duplicate of the information in the designation tag anyway. Parish boundaries also sound like a thing we would have imported at some point anyway so making that more human readable seems like something that isn’t hugely useful (or are these distinct from the admin_level=10 ones?).

I think this is a spurious argument, consistency with the key isn’t important, consistency with the value might be.

To my mind the “synthesised” ones are basically made up OSM stuff to compensate for when a Council hasn’t made up their own system. If they have made up their own system I think it makes more sense to just use theirs (as long as their refs are unique).

For the benefit of our data users, I think it’s important to use a consistent prow_ref format for each Surveying Authority (County Council or Unitary Authority). A subtlety that may not be obvious is that the legal rules that underpin Public Rights of Way require each Surveying Authority to maintain documents that are known as the “Definitive Map and Statement” which officially records the Rights of Way in their area. There are then various mechanisms that allow changes to be made through legal orders. Depending on the council they may be more or less consistent in the reference names/numbers they use to refer to the Rights of Way in these legal documents.

Separately from the legal side, the Authorities will also typically maintain a GIS system containing an unofficial or working version of the Definitive map. For convenience / each of use / limitations of the GIS system, the Rights of Way are often assigned a numerical reference, and usually broken into segments as well. These numbers are just internal references used by the Authority, rather than the legal/official number of the Right of Way. (There’s one exception that I know of - Worcestershire - where the Council actually went to the trouble of renumber all their Rights of Way and splitting them into the links/segments in order to fit their GIS system.)

For the prow_ref key, I think we should be using something that is as close as we can get to the legal name/reference of each Right of Way, rather than the Authority’s internal GIS number. In my tool at https://osm.mathmos.net/prow/ I’ve tried to work out what each Authority uses when referring to Rights of Way in its legal documents (e.g. how different paths are referred to in the Definitive Statement and DMMO applications). As you can see from https://osm.mathmos.net/prow/ref-formats/ there are a number of different formats used across the country. I don’t recall exactly what I based the decision for Cornwall on, but I would have done my best to work out what format they used.

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Have given this some thought, I take approach suggested by Robert_Whittaker. I believe we should be using the prow_ref key to document the legal name(s) used in the official PRoW documents, and not the GIS name/number or a format we believe is better

Robert_Whittaker has provided an excellent resource that documents the legal naming style used by different Authorities (link). For Cornwall it is [Parish Name]␣[Type]␣[Num].

eg prow_ref=Maker-with-Rame FP 13

I would argue that OSM should supply data that is useful for the end user. I would support a second OSM created ref key to provide a consist format PRoW name key which should be more useful for end users.

For example OSM contains the follow prow_ref

  • prow_ref = BA27/1

The format is not user friendly, but is correct. I’d be happy for OSM to have a key that translates that into standard more useful format. This would be unacceptable to many who believe OSM should only record facts. But I think it would be a reasonable function of OSM. So I’d suggest an OSM PRoW ref tag that provides a consistent format for end users. Something along the lines of.

  • ref:GB:osm_prow_ref=Parish_Name_Prow-type-Abbreviation_PRoW-Number.

So for example we’d have both
prow_ref = BA27/1
ref:GB:osm_prow_ref=Keynsham FP 1

The prow_ref tag should contain the ref as provided by the authority authorised to assign them. OSM should /not/ be making up their own. No one within OSM would suggest re-referencing Britain’s motorways & A roads, so it’s baffling why it’s deemed acceptable for the country’s PROWs.

Road refs are consistent nationally only because the authority that decides what the refs should be, is national. OSM doesn’t amend them to suit the foibles of a few contributors so neither should they be revised for PROWs.

That different local authorities have different reference formatting standards is irrelevant to OSM. The suggestion there has to be GB wide conformity is moot. The only “consistency” should be with whatever referencing system each individual authority decides to use.

The group OSM database users are are most likely to converse with regarding PROWs are the local authorities who assigned the values. Providing them with made up references will most likely illicit a response of ‘We have no idea what that means’.

“prow_ref” values are not OSM objects, objectively or otherwise.

Is there an authority who hasn’t developed their own system? I’ve not come cross one in my limited search. Cold anyone provide an example?

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Please provide a link showing Cornwall Council using “[Parish Name]␣[Type]␣[Num].” format in their “official PRoW documents”?

The database they provide & their interactive map both record paths with the format value of “539/1/2”. This is the public facing data they decided to provide & therefore the one OSM should use.

Is it the legal naming style?
I thought they were “Format Placeholders” & “are what are currently in use in RW’s PRoW Progress Tool”

If it’s “correct” it’s what OSM should be using.

OSM isn’t about ‘making stuff up’

A definitive source for the name will be documents which have a legal or legislative meaning. Cornwall Council, and most other councils, make accessing data difficult. An organisation that makes documents readily available is the Planning Inspectorate. They make the final decisions regarding PRoW.

Appeal Decision for Cornwall PRoW, and documents submitted to appeal hearing, do not use ref shown shown to the public. Cornwall Council, uses an official ref based on PRoW type - Number - Parish.

For example an appeal can be downloaded at the following link (link to Word Document download)

or below is a paragraph from that document.

  1. A copy of a map showing the Application Route was provided by the Council. However, that map incorrectly showed that the Application Route would connect with “Bridleway 2 Altarnun”. Following a request for confirmation of this matter, the Council has advised that the annotation on the original copy map is incorrect and that the annotation which refers to “Bridleway 2 Altarnun” should be read as “Bridleway 32 Altarnun”. The Council has provided a corrected plan showing the annotation “Bridleway 32 Altarnun” which is attached to this Decision for reference.
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Indeed, the same format is used in Cornwall’s Definitive Map Modification Orders (DMMOs) as can be seen on their DMMO reports page, e.g.,

Then, that’s another, obvious, reason for not using that in the prow_ref tag & use the format in the complete database provided to the public.

That’s a different format to the one you quoted in post 3 & RW’s page which you claimed was “the legal naming style”.

The data useful to the public is the data that the authorities supplied to the public, not some manipulated cinfiguration.