[Talk-GB] Prow_ref format

[Robert Whittaker (OSM lists)]

On 6 November 2017 at 11:13, Dave F <davefoxfac63 at btinternet.com> wrote:
> I'm unsure why or how often "altered reference format" happens, but would be
> a LA internal matter & irrelevant to OSM.

I haven't looked in detail at that many Authorities, but I would guess
that if you see a numeric parish code in the GIS data, then it's
likely to be an "altered reference format", as the legal documents
(written years ago, before computer systems) are unlikely to make use
of such numbers. (Unless of course an Authority has done a bulk
re-numbering of all their Rights of Way at some point.) My view is
that we should be basing our prow_ref on official the legal names from
the legal documents (The Definitive Map and Statement) and not an
internal code that's been assigned later by the Authority as a
database key in a non-Definitive database.

> We should be using the references
> provided to us under OGL even if "different LAs use different reference
> styles and with different degrees of consistency" or there's "obviously
> different de facto standard in use by an LA".

As I said before, I think it's important to note that the GIS data
provided by the authorities is generally not the official legal record
of their Public Rights of Way. So to determine the most appropriate
reference format to use in OSM, I think we should be looking instead
at the Definitive Map and Statement, and basing what we use on what's
in use there.

> OSM can't use any other format used by LA's if not issued under OGL.

I don't think that's strictly correct. We could use a different format
(on the grounds that the format itself isn't copyrightable), and it
would be ok to convert OGL-licensed refs/data to such a format
provided it could be done using only suitably-licensed data. In any
case, we often have the Definitive Statements under the OGL, in which
case, we could make use of whatever referencing system (typically
based on named parishes) is used there.

> OSM has to use a reference that relates to other databases. Concocting our
> own makes these paths impossible to be "uniformly interpreted and
> processed". AFAICS "Parish FP 12" isn't a "common standard"?

Apart from BOAT -> BY, it's exactly what Suffolk now uses in its
Definitive Statements, and also exactly what Norfolk uses in its GIS
data. (The Norfolk Definitive Statement isn't structured data, but
still uses the same elements for the identifier -- each parish is a
named heading, and then there's a sub-heading for each RoW of the form
"Footpath 12". So apart from abbreviating the type, it's basically the
same format.)

As different counties obviously do very different things, perhaps it
would be better to discuss some specifics. Is there a particular
county/authority where you think there's a better prow_ref format that
OSM should be using instead of what other mappers are using at the
moment?

Robert.

-- 
Robert Whittaker