[Talk-GB] Prow_ref format

[Robert Whittaker (OSM lists)]

On 6 November 2017 at 13:23, Mike Evans <mikee at saxicola.co.uk> wrote:
> On Mon, 6 Nov 2017 12:46:34 +0000
> Rob Nickerson <rob.j.nickerson at gmail.com> wrote:
>
>> Mike wrote:
>>
>> > A typical code is "PB|SP29|4/1"
>>
>> Be warned, this is not the format that Pembrokeshire use on the pdf scans
>> on their website. It seems to be GIS data only and may be a format Barry
>> made.
>
> Indeed so. ON the PDF it's referenced as  "SP29/4"

In this case I would go for prow_ref=SP29/4 as the Council appears to
have a clear and unambiguous reference format in use on its Definitive
Map. (My view might change if the Definitive Statement used some other
scheme, and then I'd have to decide between the two.) Since there's a
clear format I'd use that, and not artificially add parish names or
types to it. (My guess would be that the "SP29" is some sort of
area/parish/map sheet code, and the "4" is the traditional number of
the RoW within that area.)

FYI: AFAIK, the value in rowmaps isn't supposed to be a ref for use in
OSM, and has been deliberately standardised to suit the author's aims
and database structure. The initial two characters are a code for the
county, while the digit after the final slash is a segment number to
distinguish GIS objects with identical other parts of the key. What's
in the middle has been extracted from the council-supplied GIS file in
some way. In terms of OSM's prow_ref key, I think the county-code and
segment numbers should both be neglected. We don't add either to road
reference numbers for example, despite the latter being likely to
appear in GIS files.

Also, for Pembrokeshire, note that according to
http://www.rowmaps.com/datasets/PB/ , the GIS data was only released
under the "Ordnance Survey OpenData Licence", which isn't compatible
with use in OSM. I disagree with the subsequent statement there, which
implies that OS's statement automatically allows any OS-ODL licensed
data to now be used under the OGL. My view is that the actual rights
holders would have to re-license the data, as OS can't make that
decision for them. So IMO to use Pembrokeshire's data from rowmaps in
OSM, we'd need to get an additional permission/licence from
Pembrokeshire Council.

Robert.

-- 
Robert Whittaker